I have this problem right now and it's pissing me off. I'm starting to wonder if I can do anything against them. The guy doesn't even have the same name as me. He hasn't had this number for years yet I still get calls.
Under the fair debt collection act, all you have to do is tell them to stop calling you. Seriously. Just say something to the effect of "under the rights granted by the fair debt collection act, I'm informing you that you are calling the wrong number, I am not the person you're looking for and to please never contact me again" if they do, you can sue them for up to 10k for violating it. You have to do it with each distinct debt collector though. Check clarkhoward.com for more information.