I just received a call from this company that says they are Card Member Services but the White Pages, reverse phone lookup says it is a mobile phone in Detroit. Same recorded message to lower my credit card rate, when you click option 1 to get a live person to get info to report them, it hangs up. I filed a complaint with the National Do Not Call Registry. I am also getting calls from 503-468-5227, and some from Florida all I report to the Do Not Call Registry.
Its probably an automated "fisher" looking for valid current phone numbers. They can sell the list to marketers. if you answer the phone, you're on the list.