Their number shows up all the time on caller ID along w/ "Houston, TX", but they never leave a message. I, too, have relatives in Houston, TX so it is very annoying. As rich said about BofA - I guess it's b/c my husband has an old BofA account he hasn't closed. That must be why they have our number.
If you call back afterhours you get an automated system. They provide you with an option to input your phone number to be put on their do not call list. They are trying to sell insurance on credit cards.