Ok, I understand - when you said that your bank "makes good on them" I thought you meant they paid the items. You mean that they returned the items and recredited your account. This makes a lot more sense.
I agree with Greg - you ought to look into stored value cards. Sorry, I don't know offhand of a site that would explain them, but yeah, it would be a card that you "fill" with a certain value, and can "refill" again later. (A lot of universities offer this for their students/parents.)
You're probably going to have to go to a larger bank to find this service offered.