. >> reporter: attorney diane finguera. >> when you notice an unauthorized transaction, if you report it within two days of that unauthorized activity, then the bank will reimburse you for anything over $50. if you wait, if you wait for your statement to come, then the law gives you 60 days in which to report. but because you've delayed and waited, you are responsible for the first $500 of the withdrawal >> reporter: the atm industry now on alert. >> the atm operators are doing as much as they can to try to fight this it's an ongoing battle. >> reporter: and atm makers are working on ways to stop it like inserting your card sideways at least right now skimming devices can only read cards inserted the normal way. >> and that simple change has been able to defeat all static skimming devices. >> reporter: he admits that nothing is 100%. and criminals are always out there trying to defeat the latest technology. the best advice is to look for any clues thieves may have left behind like jiggling in a card slot to see if it's loose. if you can move it, don't use it always check your bank sta