It is a collection agency. They call from a variety of 206-962- #'s. They keep calling about a friend's ancient debt. Since I won't give them the other person's number they keep calling me. Better to ignore them. You can block the number, but they use different ones. So far they have used 962-5554, 962-5524, and 962-5584 (and that has only been over the last 3 weeks only).
What is the name of this collector's company? They keep calling you in violation of the law. So it would be best to send them a certified, return receipt cease and desist calling letter, report them to the proper authorities, and then sue them putting money in your pocket. Up to you.
Read up on your rights here, get template letters to send and also make a complaint at this government site: http://www.consumerfinance.gov/
Also file a complaint with your State Attorney General's office.