Part of the issue is some (chinese) ebay retailers faff around with various excuses/dialog to waste time until the time to post feedback has expired (45 or 60 days?), so the buyer who got jibbed cannot post negative ratings. And then they don't care.
My experience is that i've had a big variance in delivery time from china - anywhere from almost 1 week, to 2 days after their estimated range (5 wks?). I've only once had a faulty product (jewellery scales, didn't work). They ended up refunding the full amount, but initially wanted to just repay ~half the cost, as they said some bollocks about losing money on both the product and the postage. I stuck to my guns about them being required by ebay to repay the full amount, as well as their own refund policy. It all ended fine, but was a bit surprised they tried to pull a swifty by refunding only 50%.
Re: your situation about getting a refund then giving it back to them if the product arrives, it's your call really. Seems only fair to give them the money they earned if you get your product; and you get the (temporary) reassurance of the refund in case it doesn't arrive. Maybe a bit different if you're desperate to get it in a specific time, but that's the deal with buying cheap stuff from china and not your LHBS. Not giving you the tracking number is bollocks - I get one for items under $5. My 2c.