Ebay India - ebay is not keeping its words..

Sir
I would like to proclaim my strong protest against the ebay and ebay seller Tarun. ebay have guaranteed me that if i am not satisfied with the purchase i can claim a refund or replacement. I have purchased Logitech speakers Z103 from ebay seller gadzetz for Rs 1029. After receiving the item i found the product arrived without a valid bill. And more over i found the speakers are not shielded. In that situation i contacted email chat customer support they suggested to raise a claim under ebay 20 days money back .
The seller contacted me me and promised a full cash back @ the earliest if i send it back to him. I sent it via first flight couriers and he received it on 7 th. Till date i dint get any response from Ebay or seller. The seller is not picking the phone also and not responding to my emails. I contacted ebay chat support several times and they all promised a solution @ the earliest. Unfortunately I didn’t get a response . Always ebay guys are assuring a solution. I am fed up with false assurances and lame excuses.i have made several mails and dint get any reply from their side. I demand a refund . i have purchased new speakers from open market as i could not wait indefenitely. I feel i am cheated by ebay and seller. Now i lost my speaker system and money.
The details of the transaction is as follows
Logitech Z103 Multimedia Speaker System 2.1 17 RMS NEW
Rs.1,029.00 23/08/10 30/08/10 04/09/10 27332102043
Seller gadzetz
plz take a quick step towards my request .