You can try to reinstall windows (there is a post with all the steps you should follow for that). But it seems that there is something wrong with the hardware…
Normally GearBest recommend to go to a computer repair service and let them see what is the problem and the possible solution. Then, before they try to repair the tablet, you should contact GearBest again with the information about the detected problem, the solution and the costs of the repairs and them they decide if they pay you the repair or if you should send the tablet to GearBeast. In the case you have to send it back, if you have payed using PayPal, you can retrieve the costs of the send.