Ebay is DENYING my refund?

I have had several items I paid for that have as of yet to be received. I filed a claim. First seller says " I will send a replacement BUT you have to pay me $10.00 more. It's only fair as it was sent through USPS, an we have a tracking number to prove it was delivered". YES delivered, BUT not received! Ebay won't even go after them for violation of Ebay rules regarding additional fee charges. The second seller I made a claim, I did not see any tracking number, like what that matters, but Ebay just sent a message..... "WE deny your claim!" no answer as to why! I went off royally.Sorry but I am a vet with issues... need we go there with that?? I have had sellers try to rip me off again and again. Yeah, some I got a refund, but I had to close my previous account because I went off a few times and did not want to pay %$## *&^!@ sellers when they went off on me. Sorry! I don't appreciate being *%&#@ with! Ebay cares more about their "TOP RATED" sellers than they do about the buyers who are only looking for a fair deal and not get screwed. What to do?? Sorry 'bout my speech, just edit it. Like I said, I am feed up with companies that don't give a rats #*% about the guy bustin' his self to make a living. Now my back is against the wall going nuts trying to figure how am I supposed to get my money back if Ebay is playing this %$#^*&@ **^$^^$# game! What ever happened to the customer is always right??? Now it's *&$% the buyer, our grand sellers make us the money! I need help to get Ebay's back against the wall for a change, I will sue if I have to!