I'm having problems with eBays customer service who can I compain to?

I personally delivered items that were not as described back to the seller.  eBays Paypal protection will not refund my money as they say I cannot supply a tracking no:  I have a written receipt from my sellers employee stating these items were returned and were checked by her to be correct.  eBay has  supplied me with the sellers telephone contact details but she does not accept incoming calls. Therefore it is impossible for me to make contact this seller as they have requested to their telephone supplier not to receive incoming calls.

What can I do to get my refund as I have evidence that clearly states this seller acknowledges she wanted my bank details to issue me with a refund.  This information is in my ebay messages and yet customers service still persist that I get in contact with the seller.  I find I am going round in circles because this seller is no longer a registered member of eBay and I am finding it impossible to get hold of this person.  Can anyone help me resolve this problem please.

 Regards  needmyrefund