I have been ordering kit from China for years, never had a problem with any company I have dealt with. Customer service has always been A1, even when there is a problem with an item it has always been resolved quickly, often just sending a new one with low value items, and not even wanting the other one returned. In my experience the average Chinese company seem to be very helpful, their Government is another story!!
What puzzles me is how a company can sell a piece of used kit that they haven't had sight of. They have no idea what condition it will be returned to them in, so how do they advertise it?