The person who used to have the landline number I have was apperently a deadbeat. I used to get calls on the number all the time. I resolved it by informing them the first time that the number was now on the do not call list and that I have no idea or could care less where the other person was now, but if they called me about it again I would report them. And then when they called again, I reported them. I never got a third call.
https://complaints.donotcall.gov/complaint/complaintcheck.aspx?panel=2 Bill collectors are only allowed to call you if there is a "buisiness relationship" between you and them. I.E., you actually owe them money. Once you have informed them that they have the wrong information and that the number is on the do not call registry, they are legally obligated to stop contacting you, or be fined $500 per call. Of course, if you do actually owe them money and give them false information, and it eventually escalates to a court date and police, etc, then you are screwed if you have been reporting them and getting them fined. But in this scenario where the person who didn't pay their debts no longer lives there and is not your concern anymore, you have every reason to demand the bill collectors cease contacting you.
There is unfortunatly a lag time between when you add yourself to the do not call list and when the telemarketers are legally barred from calling you of 31 days. Thats designed to give them time to update their lists, and given that they get fined if they call you I think thats probably fair.