car won't crank

my daughter goes to a job interview one day goes to leave and her car won't
crank and it was saying starting disabled due to theft deterrent system. my
husband had to put a new battery on so he could try doing the 30 minute
reset and that didnt work and he also tried the door lock mechanism reset
and that didnt work. it has a full tank of gas but the gas hand is showing
empty and it shows error on the information center on trip A trip B,and
mileage. we had the car towed up to our local GM dealer because we had to
have 2 recalls fixed on it and we told them while they had it there to see if
they could figure out what was wrong with it this was on a Friday and on
Monday I got a call from them telling me they was having a hard time getting
the car started that it was because of the theft deterrent system but it was an
aftermarket so they couldn't do anything with it to just come get it. ive wired
the starter up to a toggle and it turns over any suggestions