Cold Calling From Call Centres ?

I have them blocked but one keeps getting through every week or two.
They women and men always start off by asking is that Mr Mole?
If you say no they then start with there selling crap.
Its normally for windows.
Some times i say no hold the line while i get him or no its Mrs Mole.
I like giving them a blast from my ref's whistle that sits by the phone
Or just hang up.
Just now when they rang i tried a new one.
I asked what call centre are you calling from?
The bloke said fuck off and hung up.
Mud.