Some ebay sellers can be problematic. I know a few people who bought servos from ebay and went for the cheapest and ended up with 4 black boxes, 4 broken circuit boards and 14 sub standaed metal gears(2 were missing).
Although i find ebay a good place for servos i have a few ground rules/ a check list i follow.
1)Who is the seller? you often find some good deals and find the sellers are from well known hobby shops or well know stores. And more often than not there will be a large number of the product available.
2)Documentation. Servos especially should have all the specs you would normally find if you were buying from a well know place. If you can cross check the spec do as some people just make them up if they couldnt care less(the people who make an effort are more reliable. but not always)
3)They should have infomation like this package includes, the payment methods, shipping time.
I am not saying that sellers who dont meet all or any of the above points are bad and are un trust worthy i am just saying that i have been following them for a while and never had a problem.
This thread got turned into a seriously off-topic flame fest, so I deleted a bunch of posts . . .
Nothing mentioned would have helped others build a robot, not even remotely . . . nothing personal!
People do take it personally when they get there hopes up. Especially when it is todo with robotics and they had plans for everything they were getting.