Where can I get help about chair not maintaining charge?

Most likely you need new batteries.

One if your not maintaining a number 1 cause is batteries nee replacing #2 is the charger is failing, however if you mean it won't go more than two days without charging then that is poor charging habits.

I’m happy to assist further over the phone at https://www.6ya.com/expert/bill_bcbb89783b08c489