Hello,
I am using QuickBooks Online and I have entered the vendor refund to my credit card as a credit card credit as you describe. However I can not find a way to then apply this to the vendor credit that I had created previously. E.g. I returned items worth $50 to vendor and created a credit memo in the system (vendor credit) for $50. However the following month the vendor refunded the $50 to my credit card. I enter the credit card credit for $50. However there is no way to match this against the vendor credit that is still open. When I try to use the "pay bills" approach that is described for matching vendor refunds via check against a credit memo it does not work because the credit card credit is not available to be selected.
