A Long time customer of Mine got U-Verse installed, He had 2 Technician/Installers hook him up. In the process, they disconnected the Alarm System which I also had a relay so they could shut the phone off at night from the keypad(they are a Doctor and don't want to be woken at night). The also disabled their Viking Doorbox/Controller that is used to communicate with the front gate, door and also open the gate.
They went to 5 locations in this house, major rewiring that was a sign of a lack of knowledge. It took 4 hours to trace out and reconnect. I called their Tech Support, they said if they come back out to correct their screwups, they will bill the customer.
I let Tech support know I am A Licensed Security Contractor and deal with many Entry/Security/Intercomm Systems that involve phone wiring and could help them. He said they have Top Techs, If so why did they screw up so bad? He also said their company is so Big, that My abilities can not be utilized, no one he can forward to?
So what will happen to Monitored Alarm wiring they disconnect?
Is this Criminal?
I think this will leave many vulnerable to non operating systems.

Even though I normally don't like to get in the middle of such things, I do understand the feelings that you have. Unfortunately, without knowing the Demark location and exactly the problem ATT techs had, it is hard to say. For 24 years I have installed telecommunication systems in businesses and homes. ATT has lost a lot of respect from myself and coworkers when it comes to typical residential or copper pair work. A lot of the original workforce was retired early and replaced with little or no experience techs that are trained on the job it appears.
With that said, they're responsible to provide the dial tone to the customers premise. One thing in businesses that I see all of the time is security techs do not follow tariff rules to stay on the customers side of a DeMark. The tariff states that the carrier has the right to disconnect service completely until it is resolved by whomever created the tariff violation. Normally, the ATT tech will just disconnect the violation and reconnect the line. It is not there responsibility to connect other companies equipment, normally that other company is called in after the installation to reconnect the equipment, properly.
Even though they went through the house doing a rewire, possibly do to problems they experienced, not sure, but it is up to ATT to inform the customer of the alarm disconnection and that's it. It is now the customers responsibility to contact the alarm company to reconnect it back in, hopefully using an RJ31X jack or similar wired properly on the customers side.