reset security system on 2000 cadillac Deville north star

My system locked my car down and I had to have my car towed to the dealer to have a new alarm install and reprogram my car that cost me $750 smh From the STEALER!!!"mind you I had already bought one that I had installed all I needed the dealer to do was program it to my car. I had already had the housing around the steering wheel off and the piece around the ignition. That's where it goes. So they didn't have to do all that labor work and they where suprise to had seen what I had done cause they made it sound like it was a big somewhat impossible job for anyone to do it but the dealers. Check out how they got me. They claim mine short circuit when they tried to program it so I had to purchase one from them and they claim they had to get it sent from Detroit Gm and had my car for5days...BULLSH#!!!!!! $750 smh

What city is that dealership in ? I won't be going . there