diff --git a/inventory-backend/app/services/inbound/buy_service.py b/inventory-backend/app/services/inbound/buy_service.py
index c79a0ea..f3d3d38 100644
--- a/inventory-backend/app/services/inbound/buy_service.py
+++ b/inventory-backend/app/services/inbound/buy_service.py
@@ -403,6 +403,8 @@ class BuyInboundService:
                         filter_conditions.append(column != value)
                     elif operator == 'contains':
                         filter_conditions.append(column.ilike(f'%{value}%'))
+                    elif operator == 'not_contains':
+                        filter_conditions.append(~column.ilike(f'%{value}%'))
                     elif operator == 'ge':
                         try:
                             num_val = float(value)