I have found that telling the marketing callers to...

"Never call this number again or I will contact the state attorney general’s
office"  Be firm but don't yell.

Works very well, if they call again, call the attorney generals office and
complain telling them the caller’s name, company, and their phone number. If
you are asked to send a letter of complant, send it! This means the company in
question is being investigated. Minnesota has strict laws regarding phone
marketing, use them to your advantage.

The marketing callers must have a list of people that take the time to contact
the attorney generals office because we do not get calls any more. Dinner time
is nice, we get to talk about our day.

Sam.