[SpainAmbassador]

Another small update:

- I said I gave up on GPD, but I told them my battery exploded and I sent them a picture of a bandaged hand. It's a last resort and I've got nothing to lose, so if it works, it works.
- OneXPlayer hasn't responded, so I sent them another email.

- Aya Neo support told me to contact the seller, which in this case was a company called Droix. After sending POP and SN and doing a little troubleshooting, they offered me to send the device for repairs.
Here are some relevant parts of the email:

Send us the boxed device with all the original accessories. Please return the item within 14 days, otherwise your return may no longer be accepted.
Package the item securely. It is your responsibility to ensure that the item is not damaged on its way back to us.

Ensure that you back up any important data before sending the item to us. All returned devices are fully wiped for security and testing purposes, and we are not responsible for any data loss that occurs as a result.
Please ensure that your parcel is sent to the following address. We are not responsible for parcels sent to an incorrect address.

Once you have posted your parcel, please send us the tracking number. Do not discard any receipt you may have received.
Once the tracking number indicates that the parcel has arrived, please allow up to 7 working days for the item to be processed according to your request.

So, I think I could box them.
FTID is out of the question, it wouldn't work in this situation.
Not sure if relevant, but they are located in the UK.
Could also go with the battery explosion story, but I'm not sure that would work either.

@mothered, do you have any advice in this situation? Thank you very much in advance.