I understand that Caller ID can be faked, so to clarify:If you MAKE A CALL to 800-421-2110, that is going to a legitimate credit card services place. (that number is on the back of my present and prior Bank of America credit card)If you RECEIVE a call, and your phone displays that number as calling, then the call is probably from that number, but the Caller ID might be faked, so the call could be from anyone.Don't answer significant questions from a call you receive, since you really don't know who is calling. Obviously if you're expecting the call then ... .If you're answering a call, get the person's name & dept., explain that you will call the number you know is genuine, and ask to be transferred to them. Then call a number you see on your credit card or statement. Using reverse phone directories on the internet to see if a number is genuine sometimes causes needless worry. Frequently, genuine numbers don't show up.