Apex alarm charged $1000 for a system that never worked , Internet

I signed up for an alarm system to be put in my house(2007).  The system was installed by a group of teenagers that showed up at my house at 11pm.  After they'd left I tried to arm the system but couldn't because even though all the doors and windows were shut the system remained open.  I called the company to fix it and had to take a day off of work to wait for them.  It turned out that they had forgotten to install a piece.  The forgotten piece was installed and the technician left but I still couldn't arm the system.  I called them again and they thought it might be the programming and they tried to help me fix it myself over the phone and that didn't work and I had to call them again and take another day off of work to wait for the technician to come to the house and fix the system.  That technician wasn't able to get the alarm system to arm. I sold the house the system never worked and now it has just showed up on my credit report that I owe them 1000 dollars for something that never worked.