The Justice Department has accused a pair of otherwise reputable banks—Zions Bank of Utah and First Bank of Delaware—of assisting scammers. It is reportedly considering taking action against additional banks as well.

When an unscrupulous telemarketer or Internet scammer gets your bank account information, he/she can’t steal money from your account on his own. He needs to find a bank willing to electronically transfer money out of your account and into his own (or into the account of a third-party processor).

According to the Justice Department, Zions Bank and First Bank of Delaware not only made fraudulent transfers on behalf of scammers, they continued to do so even as the extremely high rate of complaints from those scammers’ victims should have made it obvious that the banks were facilitating crimes. Total consumer losses are believed to exceed $100 million. First Bank of Delaware agreed to a $15 million settlement.

Banks have a financial incentive to work with scammers. They earn a fee for each transfer they make on the scammers’ behalf.

As a bank customer, your best defense is to not give out your bank account or debit card information over the phone or Internet. Use a credit card to make these payments instead. Credit cards have relatively strong consumer protections, so you are less likely to be on the hook for any unauthorized charges.

If you receive a call requesting your bank account information from someone who has a legitimate reason to have this data—a utility company that you have authorized to automatically debit your account, for example—say that you will call back. Then look up the company’s phone number and dial that.

Monitor your bank accounts closely for unauthorized debits. If the bank’s online banking system offers automatic notifications, ask to receive an e-mail notification each time there’s money withdrawn from your account. If a customer disputes a fraud early enough, the odds are good that he/she will get the money back.