I bought a bag on Ebay...it turned out to be Fake...what do I do now?

Here's my dilemma...I am only a newbie to this site, wish I had known about it before I got stung by Ebay!

I bought a Mulberry bag from Ebay for £320. It arrived yesterday and is most definately a fake.

I contacted the seller who said to post it back to them and they will then refund me. I have not yet contacted Ebay about this as I want to know where I stand.

I am not happy to post this bag back to the seller before I get a refund because
1. If the seller never refunds me, then I have no bag = no evidence
2. The cost to post the bag back will be £15 as the seller lives in another country
3. So if I post the bag back and the seller refunds me, he will only refund me the £320 for the bag, not for the postage I incurred for both having the bag sent to me and for sending the bag back....(I'll be at a loss of £30)
4. If the seller receives the bag from me and doesn't refund me, I am at the loss of £320 + £15 postage + £15 it cost for me to return bag = £350 loss.

What should I do?? Should I just return the bag? What if the seller doesn't refund me??

Help!
Thanks

 

Thanks for directing me to the correct page Shopalot.