The sad truth is that he is right^. If you took the camera off steady shot, and it is still shaky, I can only suppose it is the quality of the product. I would suggest pushing on the lens lightly and see if the screw/bayonet mount piece on either side seems loose. If it indeed is, maybe you can get it fixed.
Check out videoelectronics.tv - this is where 90% of skaters get their cameras fixed. Kerry knows everything there is to know and would be happy to give you some advice, and if there is a problem, fix it for the best price you will find. Just send him an email and explain the issue. Maybe upload a single clip to youtube and send it to him so he understands.