I have my own eBay store called extreme mobile shop. I have been an eBay member for about one year now. I have had loads of ups and downs. Down when the product i bought was not exactly like it said (every product on eBay!) and up when i have opened a store and sold loads of products i bought from wholesalers (which is always an up for eBay because they cost a arm and a leg) basically eBay is the dog biting them off .
I think business is very cut throat somebody always wants a piece of you (leg and arm again) like trying to con you on PayPal by reversing payment (yes it works) or by using the product and demanding a refund or else they will give you bad feedback.
eBay is dominated by feedback if you have bad feedback then you basically can't buy or sell much or anything. So people can threaten you by saying they will leave bad feedback and get away with anything. In this case it's a good thing not to back down. Report them on eBay, then report them on PayPal,give them bad feedback and if they try get or are let get away with one of your products report them to the FBI (How are you doing now Pedro!).
Problems with eBay and PayPal are they don't care what's happening as long as they are getting their food (money!) its very cut throat and people who usually go in to this kind of thing have lots of capital to start with. That's what makes them successful. There maybe other ways but you have to search long and hard for that and most people don't even have the time do a search on a yahoo search engine. Right now i do OK making small profits back while they get a big bite. For now it's a definite E for eBay.