Zero Liability enables you to be protected against any unauthorized purchases on your Citi™ MasterCard® account or Diners Club® account. If your card is lost or stolen and someone makes an unauthorized purchase using your Citi MasterCard card or Diners Club card, you will not be responsible for that purchase, as long as:
Zero Liability extends to any purchase you make using your Citi MasterCard card or Diners Club card, be it in a store, over the telephone, or on the web.
If you suspect unauthorized activity on your account, stop using your card and contact the issuer of your MasterCard card or Diners Club card as soon as possible.