This sort of thing happens quite frequently. Of course my experience is in the US. I live in Belize and don't use my cards very often, but when I go to the US I typically use plastic for almost everything over $100. But I have had numerous cards fraudulently charged and canceled. Unfortunately it seems to just be one of those things. There are people that make mistakes and then there are scammers, and then their are extra-ordinary con artists that love to suck our system dry.
Suck doesn't it!!!
I am intimately experiencing what you are describing and I am going through yet another card cancellation right now - try and find a US notary in this town!
Okay, as luck would have it, there is one ready and willing - thanks gal!!!