diff --git a/memberflow-api/libs/memberflow-data-1.0-SNAPSHOT.jar b/memberflow-api/libs/memberflow-data-1.0-SNAPSHOT.jar
index ba35941..ec84b55 100644
Binary files a/memberflow-api/libs/memberflow-data-1.0-SNAPSHOT.jar and b/memberflow-api/libs/memberflow-data-1.0-SNAPSHOT.jar differ
diff --git a/memberflow-api/src/main/java/com/denniseckerskorn/controllers/finance_management/PaymentController.java b/memberflow-api/src/main/java/com/denniseckerskorn/controllers/finance_management/PaymentController.java
index a88a92b..a53b52f 100644
--- a/memberflow-api/src/main/java/com/denniseckerskorn/controllers/finance_management/PaymentController.java
+++ b/memberflow-api/src/main/java/com/denniseckerskorn/controllers/finance_management/PaymentController.java
@@ -1,6 +1,7 @@
 package com.denniseckerskorn.controllers.finance_management;
 
 import com.denniseckerskorn.dtos.finance_management_dtos.PaymentDTO;
+import com.denniseckerskorn.entities.finance.Invoice;
 import com.denniseckerskorn.entities.finance.Payment;
 import com.denniseckerskorn.exceptions.DuplicateEntityException;
 import com.denniseckerskorn.exceptions.EntityNotFoundException;
@@ -29,18 +30,28 @@ public class PaymentController {
 
     @PostMapping("/create")
     @Operation(summary = "Create a new payment and mark invoice as PAID")
-    public ResponseEntity<PaymentDTO> create(@Valid @RequestBody PaymentDTO dto) throws DuplicateEntityException {
-        Payment saved = paymentService.save(dto.toEntity());
+    public ResponseEntity<PaymentDTO> create(@Valid @RequestBody PaymentDTO dto)
+            throws DuplicateEntityException, EntityNotFoundException {
+
+        Invoice invoice = paymentService.getInvoiceById(dto.getInvoiceId());
+        Payment saved = paymentService.save(dto.toEntityWithInvoice(invoice));
+
         return new ResponseEntity<>(new PaymentDTO(saved), HttpStatus.CREATED);
     }
 
+
     @PutMapping("/update")
     @Operation(summary = "Update an existing payment and adjust invoice status")
-    public ResponseEntity<PaymentDTO> update(@Valid @RequestBody PaymentDTO dto) throws EntityNotFoundException, InvalidDataException {
-        Payment updated = paymentService.update(dto.toEntity());
+    public ResponseEntity<PaymentDTO> update(@Valid @RequestBody PaymentDTO dto)
+            throws EntityNotFoundException, InvalidDataException {
+
+        Invoice invoice = paymentService.getInvoiceById(dto.getInvoiceId());
+        Payment updated = paymentService.update(dto.toEntityWithInvoice(invoice));
+
         return new ResponseEntity<>(new PaymentDTO(updated), HttpStatus.OK);
     }
 
+
     @GetMapping("/getById/{id}")
     @Operation(summary = "Get payment by ID")
     public ResponseEntity<PaymentDTO> getById(@PathVariable Integer id) throws EntityNotFoundException, InvalidDataException {
diff --git a/memberflow-api/src/main/java/com/denniseckerskorn/dtos/finance_management_dtos/PaymentDTO.java b/memberflow-api/src/main/java/com/denniseckerskorn/dtos/finance_management_dtos/PaymentDTO.java
index f53606a..0690699 100644
--- a/memberflow-api/src/main/java/com/denniseckerskorn/dtos/finance_management_dtos/PaymentDTO.java
+++ b/memberflow-api/src/main/java/com/denniseckerskorn/dtos/finance_management_dtos/PaymentDTO.java
@@ -1,5 +1,6 @@
 package com.denniseckerskorn.dtos.finance_management_dtos;
 
+import com.denniseckerskorn.entities.finance.Invoice;
 import com.denniseckerskorn.entities.finance.Payment;
 import com.denniseckerskorn.enums.PaymentMethodValues;
 import com.denniseckerskorn.enums.StatusValues;
@@ -27,7 +28,8 @@ public class PaymentDTO {
     @NotNull
     private StatusValues status;
 
-    public PaymentDTO() {}
+    public PaymentDTO() {
+    }
 
     public PaymentDTO(Payment entity) {
         this.id = entity.getId();
@@ -44,6 +46,9 @@ public class PaymentDTO {
 
     public Payment toEntity() {
         Payment payment = new Payment();
+        if (this.id != null) {
+            payment.setId(this.id);
+        }
         payment.setId(this.id);
         payment.setPaymentDate(this.paymentDate);
         payment.setAmount(this.amount);
@@ -52,6 +57,17 @@ public class PaymentDTO {
         return payment;
     }
 
+    public Payment toEntityWithInvoice(Invoice invoice) {
+        Payment payment = new Payment();
+        payment.setPaymentDate(this.paymentDate);
+        payment.setAmount(this.amount);
+        payment.setPaymentMethod(this.paymentMethod);
+        payment.setStatus(this.status);
+        payment.setInvoice(invoice);
+        return payment;
+    }
+
+
     // Getters y setters...
 
 
diff --git a/memberflow-data/src/main/java/com/denniseckerskorn/services/finance_services/PaymentService.java b/memberflow-data/src/main/java/com/denniseckerskorn/services/finance_services/PaymentService.java
index e2626be..4fb78fe 100644
--- a/memberflow-data/src/main/java/com/denniseckerskorn/services/finance_services/PaymentService.java
+++ b/memberflow-data/src/main/java/com/denniseckerskorn/services/finance_services/PaymentService.java
@@ -47,15 +47,20 @@ public class PaymentService extends AbstractService<Payment, Integer> {
         }
 
         payment.setInvoice(invoice);
-        invoice.setPayment(payment);
 
+        Payment savedPayment = super.save(payment);
+
+        invoice.setPayment(savedPayment);
         invoice.setStatus(StatusValues.PAID);
         invoiceService.update(invoice);
-        return super.save(payment);
+
+        return savedPayment;
     }
 
 
+
     @Override
+    @Transactional
     public Payment update(Payment entity) throws EntityNotFoundException, InvalidDataException {
         logger.info("Updating payment: {}", entity);
         validate(entity);
@@ -97,6 +102,7 @@ public class PaymentService extends AbstractService<Payment, Integer> {
         }
     }
 
+    @Transactional
     private void updateInvoiceStatus(Payment payment) {
         Invoice invoice = payment.getInvoice();
         invoice.setStatus(StatusValues.PAID);
@@ -116,4 +122,9 @@ public class PaymentService extends AbstractService<Payment, Integer> {
         return paymentRepository.findByInvoice_User_Id(userId);
     }
 
+    public Invoice getInvoiceById(Integer id) {
+        return invoiceService.findById(id);
+    }
+
+
 }
diff --git a/memberflow-frontend/src/components/forms/PaymentForm.jsx b/memberflow-frontend/src/components/forms/PaymentForm.jsx
index a86ec68..3b463d7 100644
--- a/memberflow-frontend/src/components/forms/PaymentForm.jsx
+++ b/memberflow-frontend/src/components/forms/PaymentForm.jsx
@@ -20,7 +20,9 @@ const PaymentForm = () => {
   const fetchInvoices = async (userId) => {
     try {
       const res = await api.get(`/invoices/getAllInvoicesByUserId/${userId}`);
-      const notPaid = res.data.filter((invoice) => invoice.status === "NOT_PAID");
+      const notPaid = res.data.filter(
+        (invoice) => invoice.status === "NOT_PAID"
+      );
       setInvoices(notPaid);
     } catch (err) {
       console.error(err);
@@ -48,6 +50,19 @@ const PaymentForm = () => {
       return;
     }
 
+    const selectedInvoice = invoices.find(
+      (inv) => inv.id === parseInt(selectedInvoiceId)
+    );
+    if (!selectedInvoice) {
+      setError("Factura no encontrada.");
+      return;
+    }
+
+    if (parseFloat(amount) < selectedInvoice.total) {
+      setError("El importe pagado no puede ser menor al total de la factura.");
+      return;
+    }
+
     try {
       await api.post("/payments/create", {
         invoiceId: parseInt(selectedInvoiceId),
@@ -61,7 +76,7 @@ const PaymentForm = () => {
       setSelectedInvoiceId("");
       setAmount("");
       setPaymentMethod("CASH");
-      fetchInvoices(selectedUserId); // actualizar facturas pendientes
+      fetchInvoices(selectedUserId);
     } catch (err) {
       console.error(err);
       setError("❌ Error al registrar el pago.");
@@ -71,10 +86,14 @@ const PaymentForm = () => {
   return (
     <div className="content-area">
       <div className="card">
-        <h2>Registrar Pago</h2>
+        <h2>Registrar Pago de una Factura</h2>
 
         <label>Seleccionar estudiante:</label>
-        <select className="form-select" value={selectedUserId} onChange={handleStudentChange}>
+        <select
+          className="form-select"
+          value={selectedUserId}
+          onChange={handleStudentChange}
+        >
           <option value="">-- Selecciona un estudiante --</option>
           {students.map((s) =>
             s.user ? (
@@ -96,13 +115,20 @@ const PaymentForm = () => {
               <option value="">-- Selecciona una factura --</option>
               {invoices.map((inv) => (
                 <option key={inv.id} value={inv.id}>
-                  #{inv.id} - {new Date(inv.date).toLocaleDateString()} - Total: {inv.total.toFixed(2)} €
+                  #{inv.id} - {new Date(inv.date).toLocaleDateString()} - Total:{" "}
+                  {inv.total.toFixed(2)} €
                 </option>
               ))}
             </select>
           </>
         )}
 
+        {invoices.length === 0 && selectedUserId && (
+          <p style={{ marginTop: "1rem", color: "gray" }}>
+            No hay facturas pendientes de pago para este estudiante.
+          </p>
+        )}
+
         {selectedInvoiceId && (
           <>
             <label>Importe pagado (€):</label>
@@ -121,15 +147,18 @@ const PaymentForm = () => {
               onChange={(e) => setPaymentMethod(e.target.value)}
             >
               <option value="CASH">Efectivo</option>
-              <option value="CARD">Tarjeta</option>
-              <option value="TRANSFER">Transferencia</option>
-              <option value="BIZUM">Bizum</option>
+              <option value="CREDIT_CARD">Tarjeta</option>
+              <option value="BANK_TRANSFER">Transferencia</option>
             </select>
 
             <ErrorMessage message={error} type="error" />
             <ErrorMessage message={success} type="success" />
 
-            <button className="btn btn-primary" style={{ marginTop: "1rem" }} onClick={handleSubmit}>
+            <button
+              className="btn btn-primary"
+              style={{ marginTop: "1rem" }}
+              onClick={handleSubmit}
+            >
               💳 Confirmar Pago
             </button>
           </>
diff --git a/memberflow-frontend/src/components/lists/PaymentList.jsx b/memberflow-frontend/src/components/lists/PaymentList.jsx
index 3168e01..ea1d3a5 100644
--- a/memberflow-frontend/src/components/lists/PaymentList.jsx
+++ b/memberflow-frontend/src/components/lists/PaymentList.jsx
@@ -48,7 +48,7 @@ const PaymentList = () => {
   return (
     <div className="content-area">
       <div className="card">
-        <h2>Listado de Pagos</h2>
+        <h2>Listado de Facturas Pagadas por Estudiante</h2>
 
         <label>Seleccionar estudiante:</label>
         <select className="form-select" value={selectedUserId} onChange={handleStudentChange}>