The best OP is going to do is to get B6 to reissue the credit to his now closed account. B6 won't vary from long-standing practice across US commerce. Thus, it will always take Chase to assist as that still would mean that a credit hits which it will need to convert to a check and mail to OP.

I would do all of this in writing because front-line customer service people have no capacity or understanding of how to deal with fact patterns which do not fit the form.