Was this return all done through the proper channels, that is, through an eBay case.
Then once a return label is received, and item posted back with that label, it gives the seller 48 hours to refund you on return of their item, if they don't, you escalate the case, eBay step in and force the refund.
Nothing can be enforced if the refund was not done on time, and through a case with eBay. You may then need to turn to your payment provider now, for help with a refund.
@dahor_629