what should I do now.
No-one has replied in over five hours, which is probably becaue by providing so little information you have made it hard work to help you
By "far too small" do you mean they were to small for you personally, or that they were not the size advertised?
Did you buy these from a UK business seller, or a private seller? What is their returns policy - it will be stated in the listing?
Have you just asked the seller for a return, or opened a return request under eBay's money back guarantee? If so, a business seller would be required to accept returns for any reason, although you would have to pay for the return if the shoes just don't fit you. A private seller would not be required to accept a return for this reason.
If the shoes are of a different size to the size advertised then either a business or a private seller would be required to accept the return, and to provide a prepaid return label.
If you have already opened a case and the seller has refused it you need to escalate it for eBay to step in. If you haven't followed the returns procedures that eBay provides you can read about them here:
https://www.ebay.co.uk/help/buying/returns-refunds/return-item-refund?id=4041
https://pages.ebay.co.uk/ebay-money-back-guarantee/
A case MUST opened within 30 days of the date of delivery. Just read and follow the process - if there's anything you're not sure about people here are always willing to help.
