If you haven't done so already the option to escalate your case to ebay will appear 3 complete working days after you started it. Go to the return case, 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 callback link on here:
https://www.ebay.co.uk/help/eua?id=5275&mkevt=1&mkpid
