1998 Dodge Neon Car Alarm Problem

HELP me please. My car had a car Black Widow car alarm when I purchased it. The previous owner gave me the remote controls and for a long time it worked fine. One day the alarm remote would just not disengage the alarm. I tried changing the battery in it but nothing. The alarm had a starter cutoff on it so I cant start the car. The engine doesn't turn, you only hear the gas line spray but the car will not turn on. I took I to the mechanic and he told me that I should disconnect my car battery to reset the alarm system so it would turn on. I did this and For a while it worked fine but now it just won't start. Can a regular mechanic fix this? Who can I go to in order to get the alarm taken off so I don't run into this problem anymore? I don't even need the alarm! PLEASE HELP! I really need my car to get around for work and for the last month i've been carless! I'm so lost about what to do!