Bug in payment system for rated game

I just had one of my tournaments rated. The total was for 18 rated games, which comes to 4.50. I tried to add 1.00 to the Players Health Fund (or whatever it’s called); the total came up as 5.50, but when I went to pay with the credit card, it reverted to 4.50. Can anyone confirm the bug and, if it’s real, can we get it fixed?