Purchased

[c3mad]

I thought i had purchased an item a specific vehicle .no size was given but i assumed it was special to a vehicle .it turns out to be one size fits all and yet it specifically said was for my car only . To give you some idea it was a cover for a bumper when i received it the cover was half the size of the bumper so not completely accurate on the description. see attached picture would you say this is specifically for a Citroen berlingo 
now the seller is refusing to accept a return 

[jckl1957]

If you bought from a business seller, they have to accept returns for any reason.

If it was a private account and you started a return using the reason 'wrong size/doesn't fit' then the seller can refuse the return because that is considered a change of mind return.

If the listing was deceptive and the item is not as described in the listing, then you could go to your payment source and start a chargeback.

[red_magpie]

now the seller is refusing to accept a return

Did you open a case under eBay's money back guarantee? The seller couldn't refuse this if you followed the procedure carefully. Unless possibly you said that it didn't fit? (Buyers MUST make it clear that an item doesn't match the description as eBay treats "doesn't fit" as a change of mind return. This stems from eBay's policy that correctly described clothing is not returnable under the guarantee just because it doesn't fit the buyer. eBay cannot seem to grasp that replacement parts for cars that don't fit are not just a change of mind!)

Or did you submit an ordinary return request? If the seller's returns policy is to accept returns, they couldn't refuse this either. 

Or did you just ask the seller for a return, without using any of the procedures that eBay provides?

It's so very hard to provide meaningful advice if you don't give us any information. We don't even know when or how you paid, on which so many of your rights depend.