Are you going to ask her to reimburse you? If your not, then I wouldn't even bother (but then again, I'm not very confrontational..so many that's the wrong approach). I'd just wait for her to try the card again and then she'll get the gist of it when it doesn't work.
In the end, it's not the years in your life that count. It's the life in your years. Abraham Lincoln
It is hard to fail, but it is worse never to have tried to succeed. Theodore Roosevelt
