diff --git a/api/serializers.py b/api/serializers.py
index 94d3543..d786705 100644
--- a/api/serializers.py
+++ b/api/serializers.py
@@ -115,79 +115,95 @@ class RegisterSerializer(serializers.Serializer):
             email=validated_data['email'],
             password=validated_data['password']
         )
-        SupplierProfile.objects.create(
+        SupplierProfile.objects.update_or_create(
             user=user,
-            phone=validated_data['phone'],
-            status='unverified'
+            defaults={
+                'phone': validated_data['phone'],
+                'status': 'unverified'
+            }
         )
         
         is_test_user = validated_data['email'].startswith('test_seller_') or validated_data['username'] == 'demo_seller'
         
-        wallet = Wallet.objects.create(
+        wallet, _ = Wallet.objects.update_or_create(
             supplier=user,
-            outstanding=850.00 if is_test_user else 0.00,
-            withdrawn=1250.00 if is_test_user else 0.00
+            defaults={
+                'outstanding': 850.00 if is_test_user else 0.00,
+                'withdrawn': 1250.00 if is_test_user else 0.00
+            }
         )
 
         if is_test_user:
             # Seed default products
-            Product.objects.create(
-                supplier=user,
-                title='Silk Scarf',
-                category='Apparel',
-                price=45.00,
-                stock=25,
+            Product.objects.update_or_create(
                 sku=f'APP-SILK-{user.id}',
-                image='https://images.unsplash.com/photo-1544022613-e87ca75a784a?auto=format&fit=crop&q=80&w=100'
+                defaults={
+                    'supplier': user,
+                    'title': 'Silk Scarf',
+                    'category': 'Apparel',
+                    'price': 45.00,
+                    'stock': 25,
+                    'image': 'https://images.unsplash.com/photo-1544022613-e87ca75a784a?auto=format&fit=crop&q=80&w=100'
+                }
             )
 
             # Seed default orders
-            Order.objects.create(
-                supplier=user,
+            Order.objects.update_or_create(
                 order_id=f'OR-8721-{user.id}',
-                date='2026-08-05',
-                item='Handmade Wool Blanket',
-                quantity=1,
-                customer='Alice Smith',
-                total=85.00,
-                status='Pending Acceptance'
+                defaults={
+                    'supplier': user,
+                    'date': '2026-08-05',
+                    'item': 'Handmade Wool Blanket',
+                    'quantity': 1,
+                    'customer': 'Alice Smith',
+                    'total': 85.00,
+                    'status': 'Pending Acceptance'
+                }
             )
-            Order.objects.create(
-                supplier=user,
+            Order.objects.update_or_create(
                 order_id=f'ORD-8501-{user.id}',
-                date='2026-08-08',
-                item='Brass Elephant Figurine',
-                quantity=1,
-                customer='Bruce Wayne',
-                total=120.00,
-                status='Pending Acceptance'
+                defaults={
+                    'supplier': user,
+                    'date': '2026-08-08',
+                    'item': 'Brass Elephant Figurine',
+                    'quantity': 1,
+                    'customer': 'Bruce Wayne',
+                    'total': 120.00,
+                    'status': 'Pending Acceptance'
+                }
             )
 
             # Seed default returns
-            ReturnRequest.objects.create(
-                supplier=user,
+            ReturnRequest.objects.update_or_create(
                 return_id=f'RET-5510-{user.id}',
-                order_id=f'OR-3920-{user.id}',
-                customer='Bob Johnson',
-                item='Silk Scarf',
-                reason='Ordered wrong color variant.',
-                status='Pending Approval'
+                defaults={
+                    'supplier': user,
+                    'order_id': f'OR-3920-{user.id}',
+                    'customer': 'Bob Johnson',
+                    'item': 'Silk Scarf',
+                    'reason': 'Ordered wrong color variant.',
+                    'status': 'Pending Approval'
+                }
             )
 
             # Seed default wallet transactions
-            WalletTransaction.objects.create(
-                wallet=wallet,
+            WalletTransaction.objects.update_or_create(
                 tx_id=f'TX-9031-{user.id}',
-                date='2026-08-01',
-                amount=500.00,
-                status='Transferred'
+                defaults={
+                    'wallet': wallet,
+                    'date': '2026-08-01',
+                    'amount': 500.00,
+                    'status': 'Transferred'
+                }
             )
-            WalletTransaction.objects.create(
-                wallet=wallet,
+            WalletTransaction.objects.update_or_create(
                 tx_id=f'TX-9022-{user.id}',
-                date='2026-07-15',
-                amount=750.00,
-                status='Transferred'
+                defaults={
+                    'wallet': wallet,
+                    'date': '2026-07-15',
+                    'amount': 750.00,
+                    'status': 'Transferred'
+                }
             )
 
         return user