Third day as a telemarketer and I've lost all respect for people who, instead of taking the time to find solutions for their problems, become very angry and take it out on people who have no control over the solution.
Unrelated, Here's the links for the Do not Call registries for Canada and the states. plus most european countries should have one too.
Also, fun fact: if you give your phone number to a company who then sells it's list of numbers to other companies, none of the other companies know if somone requested that one specific company stop calling them. All the companies do respect the do not call registry, as the fines for violating it is so hefty that even the most janky ass number databases supports cross checking against the dnc list.