I've had good success with my credit card companies canceling cards the couple of times I've found fraudulent charges. And once, Chase even canceled before I asked (back when Hannaford Supermarkets had a problem with hackers). I keep 2 major cards just in case I have a problem with one.
Damn scammers!!!
The credit card company noticed the fraudulent charges and called me to ask about them. I actually found out when I went to buy something and the card was declined. The call had come in just after I left the house. We went through the last two weeks of charges and there were a bunch that weren't me and a bunch that were. I'm glad they have software that alerts them to unusual patterns. I'd rather they be aggressive about it than the other way. I really don't want to feel I need to check my credit cards every day or two to see what charges are there.
Our credit card company is great about detecting unusual patterns and they text right away. Last text I got was when I bought two plane tickets to Johannesberg for ~$4000 ;)
We got a call about lots of charges from Canada in mid August. :-). But I think they figured it out without us telling them because the card continued to work.
They're usually pretty good about sending out a new card fairly quickly, too.
We've partied hard in Vegas before, and have bought several sets of very expensive tires.
I've had the fraud detection be a real problem before though, while on a trip in a place with no cell service. Declined while trying to pay for dinner for my hosts and their extended family!