User Activity

I was selling something and the buyer didn't pay, so I opened an unpaid item case. Someone from eBay messaged me to say that I can request payment from the buyer again, but I never got it. About a month later, the buyer leaves me a negative feedback ...
There is this buyer who first of all takes almost an entire month to pay, and then lists a fake shipping address on his eBay account so you waste shipping fees shipping to a non-existent eBay address. Then he files a claim on Paypal, and Paypal, hist...
Sometimes- even as much as 50-60% less. The only difference I'm seeing is that competitors have nicer-looking listing layouts and some with far more feedback. The catch is most of my items are less than $4 each... are buyers really that sensitive to ...