I have no power myself over a refund. For all issues of refunds, billing, payment, subscription terms and status, etc., I must refer you to Customer Support at JustAnswer.com, which may be contacted through:
They will no doubt address your concern, if you contact them, with reasonable promptness.
I admit that I have no further help to offer, except to say that we both agree as to what was the sensible thing to do. (And though your auto was bought used, you could still take it to a dealership in that sort of car, to see if they can help you get the radio code for it. That wouldn't be under warranty or anything, as a service, but it would not be in any case, I don't think.)
I have Opted Out, opening the case to other Experts in case another Expert has the information you need before the refund is issued. Thank you for bringing your question to us here at JustAnswer.com.