First thoughts:
A hearing aid is basically a microphone feeding into an amplifier, and then into a speaker (= earpiece). Dozens of Chinese technology companies can put that lot together for under a quid.
OK, what 'Hidden Hearing' offers is probably a bit more advanced than that, but do you really believe that what's on the chip inside their device is so special that it needs to be priced in line with the cost of a dozen good quality laptop computers (each of which contains hundreds, or possibly thousands, of chips of equal quality)?
It's a con!!!!
Get your aunt to go to her GP. He'll arrange an appointment at a hearing clinic. Then she'll get a perfectly good hearing aid, free of charge, courtesy of the NHS.
Still don't believe me? See here:
http://www.express.co...er-hearing-aid-refund
Chris