I have to agree with Sweedish Chef. But then again, I was a collection manager before I became a C/O. If your bank has internet banking it doesn't matter if you were out of town. You could have checked your balances daily and transferred funds. I hope I don't offend, but your original post implied that you were using one account while your other account went O/D. On the other hand, the bank should have just offset the O/D account with the account that had "plenty of money" and then didn't have to block access to the card.

I see this situation as a difference in expectations. Your bank expected that your overdrawn account would be corrected. It may not ordinarily exercise set off against other balances, and its practice may be to "get the depositor's attention" by blocking a debit card.

Your expectation is (or was) that the bank would move the funds to cover the overdraft on its own initiative, before resorting to something like blocking a debit card.

If you and the bank sit down and have a calm discussion about the situation, and you ask about whether you can set up an automatic transfer to cover you if you slip up, you and the bank might end up with similar expectations.

Both Visa and MasterCard operation rules allow a card to be blocked if the bank feels it is being used in a fraudulent way. However, what you described is not that situation - Visa and MasterCard regulate their cards, not the accounts they may be attached to. While Swedish Chef may have an opinion about appropriate behavior, V and MC do not want their brands jeopardized by the whim of an overreactive bank and their association agreements are construed with that viewpoint in mind.

This is not to say that your state doesn't have some sort of law that allows this blocking - or absense thereof, the bank has instituted its own policy which may as I stated violate their association agreement. Truth be told, you have no recourse beyond filing a complaint directly with Visa or MasterCard. However, please note you can still write a check.