That sucks what you're going through and wish we could help here as a group but even if eBay restores the balance of power on the feedback system, it would only work for the smaller majority of dishonest people as the more professional harden criminals would still be in operation.
I quit selling long ago not only because I wanted to protect my 100% and over 680 perfect transactions (not all at selling either), but the hassles of the deadbeat, non-paying, buyers-remorse people were getting more and more frequent and then the BIG change in the feedback system which is VERY unfair... my bank account was more important than making a buck.
I just hope things can remain civil here on RCU as I have sold quite a few things in the past and had no issues. But of course I only deal with those I really know and trust.