When I canceled one of my accounts it was many months before the changeover. The card details hamster has a long memory
I used the sticky guide on Uhall to find and nuke card details from my account.
Did you look for card details before you spoke to EA/Mythic? I'm just wondering if maybe a CSR had removed the billing info before you logged into account management. If not, I'm not sure where the info would have been. Mine was right there when I went to re-activate the account, I had the option to select that card and that's when I realised the old details had carried over. The system had to have the card info to bill it, so either it was removed by a CSR or something weird is going on.
If the charge was canceled at EA/Mythic's end, I would expect that you won't be charged again. But you should keep a very close eye on your bank account a few days before the next payment would be "due" on their system. Just in case you do get another charge. Then it's up to you if you block the account for further payments to EA/Mythic. But you should be able to get your bank to issue a fresh card without being marked as fraud. Especially when this isn't your fault, it's down to the billing hamster going a bit daft. You're quite within your rights to take that sort of action when a payment is taken without permission.
Wenchy