WARNING: ignored my 30 day refund request, then told my bank I never contacted them
Posting this as a heads up for anyone thinking of buying, or anyone currently trying to get a refund.
Device arrived 19 August. Used it an hour every day as instructed and felt no difference at all. On 4 September, well within the 30 day money back guarantee, I emailed their care address to start a return. That's exactly what their own refund policy says to do, and their help centre says they reply within 2 working days. Nothing. I chased on 13 September. Still nothing, not even an auto reply.
So I raised a chargeback with my card provider. That's when they finally responded, but only to the bank, claiming I'd never contacted them and that their inbox had "no record" of my email address. Which is interesting, because their care address had emailed me at that exact address about my order weeks earlier. I have all the emails.
I'm still fighting it through the bank and I'm prepared to go to small claims if I have to.
If you're trying to return yours, my advice:
Email them and screenshot your sent emails with the date, time and full address showing
Chase once in writing and give them a clear deadline
If there's no reply, go to your card provider for a chargeback (or Section 75 if you paid by credit card in the UK and it was over £100)
Keep EVERYTHING, because they may deny you ever contacted them
Judging by the reviews on Trustpilot I'm far from the only one this has happened to. Personally it feels like a scam to me. Be careful, and if you've had the same experience, share it below so others can see.