from happening again. >> we could get to the bottom of how target's in-store security payment was compromised in order to make sure that target in the future and all other stores adequately protect consumers from this kind of devastating theft. >> reporter: some customers in california have already filed what could become a class action lawsuit against target saying the chain failed to implement and maintain reasonable security procedures and practices. target said on sunday it notified millions of affected customers via e-mail and is working with the secret service and financial institutions to resolve the problem. they also offered customers 10% discounts this weekend as well as free credit monitoring. according to national retail federation, we could see more problems like this in the future, simply because of the magnetic strip on the back of these cards, technology they say