I just moved into a house with a malfunctioning security system that I'd like to have taken out.

I can't get in touch with the company that installed it, and the electricians I call say they won't touch it.

What type of contractor would handle something like this?

Thanks,
Radley

Why don't you just disconnect the siren and the telephone connection? This way the alarm will seem like it is still working, but not call anyone nor set off any noisy alarm?

A competitive alarm company might be happy to make sure it never gets fixed up. You may get a hard sell on a new one.

Once unplugged or the circuit breaker opened, you could cut off all the exposed wires and components yourself and toss them.