If you haven't done so already escalate your case to ebay. You should have been given a date to do that in the email you got from ebay when you started it, usually at least 3 working days later. Go to the return case via the link on the ebay message, click on Case Details > Respond to Case > Escalate This Case > Submit.
If you've done that or if you still have problems contact eBay using the chat link on here:
https://www.ebay.co.uk/help/eua?id=5275&mkevt=1&mkpid
