Send a registered letter telling them that you are not going to deal with the matter and stop calling. Keep proof of the letter and date they signed for it. If they call after that, call the CRTC.
Another one of the many stolen numbers used by Contact Resource Services to get to people, they believe owe them money. I happen to have the same name as a guy who owes them money. I even sent them ID that shows my middle name being different than the person they're looking for. But every few weeks they call again, and I answer "Yes" when they ask my name, and we go through the same discussion over and over again. Who do I call to stop this harassment?
Yep, another debt collection agency. They lie through their teeth, saying that they took me to court, and they never did. I know that they were lying when I asked where the court house was. They gave a wrong answer, because there is no court house in their answer.
Send a registered letter telling them that you are not going to deal with the matter and stop calling. Keep proof of the letter and date they signed for it. If they call after that, call the CRTC.
I answer and wait for them to come on line. Then I speak very softly so they become extremely intent on listening. I then blast them with a bear horn. After a couple of calls, they never call back.
You can get a bear horn at most camoing type shops.