Lancer Alarm Glitch

I recently took my 03 Lancer to best buy to get an alarm installed. They did a crpapy job, for some reasong they were not able to install the alarm correctly. The techs could not pin point the problem. Went to 3 best buy and nothing. Finally pulled the damn thing out. The only thing that aould work was the keyless entry. The lights never flashed and the siren would go off when it wanted to. Any one know what the hell is going on?