But this is one of the times that phone number on the back of your card comes in handy. (blog.tortugabackpacks.com)
For all credit cards and debit cards, write down the account number AND the phone number on the back of the card so you can call. (thecollegeinvestor.com)
Once you decide to close a credit card, you'll need to give your card issuer a call using the contact number on the back of your card. (thesimpledollar.com)