I don't trust eBay sellers for my silver. I would use eBay to sell...not buy (of course, we'll have to get to the next paradigm first where people are paying me with something other than useless green paper)...
I also recommend that when you buy from reliable and trustworthy sources (Apmex, Provident, Miles Franklin, etc) save your receipts showing where it came from. If you ever have to PROVE authenticity OR that you are the legal owner, receipts will help. You never know when government thugs may try to say your precious metals were purchased with 'drug money' and attempt to confiscate. With receipts, you can trace the source of your funds and show it was paid for from a checking account, bank wire, etc.
“Let it not be said that no one cared, that no one objected once it’s realized that our liberties and wealth are in jeopardy.”
― Ron Paul