I had this happen to me a few years back...only I did see unauthorized charges on my card because I too, had set up email alerts whenever a transaction over $1 went through. Suddenly I started seeing alerts coming to me for $1 iTunes transactions that I never made...this is what the thieves were using to "test" my card. Unfortunately, they were able to use the card for a total of about $600 before I alerted my credit card company to cancel the card. I swear those email alerts are the best thing ever. Had it not been for those alerts, I would not have noticed the charges until my statement arrived in the mail...and who knows how much the thieves could have racked up in charges by that point. Perhaps calling your credit card company and letting them know that your card info may have been compromised, might be a good thing to do. They may take extra care and precautions when a transaction for that card goes through to make sure it's not a bogus charge.