I used to do an evening office cleaning job, to supplement my daytime job wages, (as a single parent bringing up three boys). It was a company for life insurance and pensions etc. The staff would be there until after 8pm with a phone book in front of them just ‘cold calling’. I used to ask why...
I have a little ‘polite notice’, bought off Amazon, stuck on my front door.
It states, ‘ NO cold callers
Canvassers
Salesmen
Or
Religious Groups
It really does work! If someone ignores it, I ask them...