diff --git a/make_post_sell/views/cart.py b/make_post_sell/views/cart.py
index 99115ca..8aea20a 100644
--- a/make_post_sell/views/cart.py
+++ b/make_post_sell/views/cart.py
@@ -1091,7 +1091,13 @@ def paypal_complete_checkout(request):
 
             for invoice in successful_invoices:
                 for line_item in invoice.line_items:
-                    cart.remove_product(line_item.product, line_item.quantity)
+                    # remove_product takes (product,) — drops the cart
+                    # entry entirely regardless of quantity. A previous
+                    # pair passed quantity as a second arg and was
+                    # raising TypeError "takes 2 positional arguments
+                    # but 3 were given" — which silently 502'd via the
+                    # pyramid_tm tm.abort path until tm.doom landed.
+                    cart.remove_product(line_item.product)
             cart.update_inventory(request.shop_location)
 
             for invoice in successful_invoices:
@@ -1342,7 +1348,13 @@ def adyen_complete_checkout(request):
 
             for invoice in successful_invoices:
                 for line_item in invoice.line_items:
-                    cart.remove_product(line_item.product, line_item.quantity)
+                    # remove_product takes (product,) — drops the cart
+                    # entry entirely regardless of quantity. A previous
+                    # pair passed quantity as a second arg and was
+                    # raising TypeError "takes 2 positional arguments
+                    # but 3 were given" — which silently 502'd via the
+                    # pyramid_tm tm.abort path until tm.doom landed.
+                    cart.remove_product(line_item.product)
             cart.update_inventory(request.shop_location)
 
             for invoice in successful_invoices: