The whole business model is evidently blatant theft. If you don't get what you ordered, or it is defective, you have ZERO recourse. I'm going on three months now from initial order and still don't have a refund. They just keep doing obvious delay tactics instead of shipping a replacement or refund. This is an open and shut case of something that overheats and damages what is attached to it. They made me make videos of it, tried to get me to try all the different modes (completely irrelevant, and again would damage whatever was attached to it), then shipped me a tiny/cheap part that would not resolve the issue in any case, and I'm supposed to open the thing up and repair it!
DO NOT BUY FROM THEM THEY ARE THIEVES.
I have a lot of experience with Aliexpress, dhgate, bangood etc most of the "order cheap crap straight from China, if you're willing to wait a long time for shipping" places, and Fasttech is not just the absolute worst in my experience, but the more I look into it everyone says they've had terrible experience within a few orders. I don't know how they stay in business!