I had a problem with 1st free year domain but now wix owns it

Question:
I had a problem with 1st free year domain but now wix owns it

Text:
So today my client bought the premium plan for his website and after that tries to get the 1st free domain year but can’t really get it. He gets the domain anyway and I now need to get him a refund for the faulty voucher code.

Getting help from an expert on the phone saying there is nothing he can really do, escalated the case to another team. But now, my client doesn’t have the domain he bought nor the refund.
Wix has the domain and we just can’t do anything beside trying to see if you guys have the answer.

Any advise?