Duff battery due to lack of routine maintenance etc has probably knackered the charging circuit and the pcb, it's had a good innings though!-more luck than anything else I would hazard a guess.
Have you enabled flex set for that user?
You have to enable flex set globally and then for each user.
im not sure if it's needed as I always have one set, but you may need a zone setting as FX or ER
You also need zones assigned to area A & B to uses areas A & B !