Why don't we store credit cards anymore?

On our old website we had an integration with Authorize.net CIM. This allowed us to tokenize your credit cards so you didn't have to enter them each time. We think it is safe however, over the past several years there have been some customers who thought their credit cards were stolen on our site. And we don't believe it to be so but we can't prove otherwise. This certainly damages our reputation and we have decided we cannot risk this. We all remember this Target Hack