Baggiesfaninessex, just to stick to your question:
indeed, noone can refill their balances at fiesta as for now. and noone, including aom3 admin/moderators/senior members is aware of the decline reasons. thus, there is
not a single chance for anyone to learn more. you have to keep patience and wait while they're up again.
yet there's no need (for a lot of reasons) to raise such questions -- even if your learn the exact reasons (which is never going to happen) of their payment system being down, you still will be unable to do anything, right?
i really hope my post was somewhat helpful.
regards,
Max