We don't know what procedure you followed through eBay to request this return but your seller's returns policy is to accept returns so if you raised the request correctly through eBay and uploaded a tracking number to prove delivery you should have no trouble in getting one.
If you made a DIY return without going through eBay, eBay won't be able to help. This may be a problem, because although the seller seems to have a distribution base in Birmingham, they are actually in China. Unless done through eBay, enforcement of returns and refunds against sellers in China is likely to be impossible.