Which carrier was used for you to receive the item?
If you open a case for item not as described, the seller has to provide that correct return label, preferably then, using the same carrier for the item's return.
If the seller provides the wrong label, then Contact eBay Customer Services, explain the issue, they'll reissue the label, and charge it to the seller's account.
This is the easiest and quickest way to contact eBay Customer Services, for a Call Back option.
https://www.ebay.co.uk/help/eua?id=5275&mkevt=1&mkpid
Lines open between 8 a.m. to 10 p.m. on weekdays.
9 a.m. to 6 p.m. on weekends.
I recommend contacting CS very first thing in the morning, when the lines first open, as there's more chance of Dublin answering.
@joshesmanta