I would outlaw cold calling

How do I get my own back on Everest Windows? The bastards called me on the dot of 9.00 this morning -- on my own very personal mobile phone. This is because I had a quote from Everest Windows in the summer. I told them that I would never buy their windows if they ever spammed or junk mailed me. They started to do that at once, so I chose a local firm who did it for half the price.
For weeks now they have been cold-calling me. I have threatened to go and blow up their toilets. It makes not the slightest difference. And apparently I am unable to vent my anger on the sulky girl who does the cold calling for them. It's called harrassment.