You're going to have a hard time getting a replacement wheel for an eBay turbo, unless you can find one from wherever you bought it from. There isn't any guarantee that standard replacement parts will fit your turbo, and there really isn't any way to check that, so there really aren't many options left. I'd cut your losses and buy a better turbo. A rock is a rock, and will fuck up any turbo, but if you have a reputable brand then at least you can get rebuild/replacement parts for it.