Make an appointment and invite them round.
Do not answer the door bell.....you did not hear it. 
That's a bit like the stunt I pulled on a persistent double glazing firm some years back . . .
They kept pestering with telesales calls. I was living in a flat at the time - second (top) floor.
I said "My windows are already double glazed", they suggested I could have a conservatory!
I said "I don't you'll be able to do that"
Response: "we can fit them anywhere!"
So, I made an appointment.
The due time/date arrived. Door bell went, on intercom I said "come on up, second floor"
Salesman arrived. Was a bit nonplussed (lovely word that), asked "is the conservatory for somewhare else?"
"No" I replied, "here. Your telesales told me you could fit one anywhere, so, fit one out there please"
His response? "You"re having a laugh"
I said "No. Now piss off and tell your telesales to stop bothering me!"
To date I've not heard a peep from that company . . . .
Top tip! 👍
