Runpod won't take my money

I'm trying to pay money to runpod, adding $200 at a time, with a burn-rate of about $8/hr, but runpod has decided not to accept my money and I am now down to $35 left in the account. Is there any way to solve this? I've called my card provider and they've said that it's not an issue on their end (i.e. they have not blocked runpod)? Would be great to get a solution to this soon (ideally)