They likely got told to knock it off since Visa, Mastercard and Amex don't allow refunds without associated charges.
Credit cards arent like bank accounts, Unless its a prepaid debit card.
You can't legitimately load money onto a credit card because there is a very limited number of transactions you can do
Auth
Post Auth
Sale
Refund
Void
There are a couple more but its likely that they are trying to "load" credit cards via a refund without an associated sale which is a no-no.