Don't wholey understand why it has to goto china under a waranty thing, and they can't just replace the thing locally.
In anycase, if they want, they can ofc just stick a new controller over it and load everything off - if it is infact the case the controller is bust. Trust them ? Probably not tbh. I wouldn't trust any1, even a reputable firm - they would ofc on the face of it be legit, but it only takes 1 employee, without the company's knowledge to rip it.
A data recover firm would get it up and running I'm sure - that is going to cost u a fortune. Even for 32g.
Got any large sources of EMF ?