keep getting 2-3 calls a day and I am in Manitoba

2 call from this number today. They did not leave a message.

I keep getting calls from this number, but I will not answer and they do not leave a message. Yesterday, July 6th, I received 4 calls during the day. Extremely annoying. Not to mention, my number is on the do not call registry. Makes me wonder what in Gods name the purpose of that is!