Avital Security Alarm Question

Hello, I have an Avital security alarm installed in my 2000 Honda Coupe. The remote autostart, trunk entry, silent entry, normal entry were all working fine until it was taken in for an oil change at a nearby mechanic shop. When it was returned, for some reason, the alarm doesn't work at all. I've tried turning the power switch for the alarm (located under my steering wheel) on and off but while the blue light, which used to turn on whenever my alarm was activated still works, the car will not respond at all to any of the buttons. The body shop denies doing anything wrong (even though I suspect they must have removed the battery or done something they are trying to cover up) I haven't taken it to a shop yet but if they tell me that I need to reinstall this entire alarm again,   does that sound okay? Isn't there anyway to reactivate an alarm system? or do alarm systems die when fiddled with by people.. Thank you for your comments/suggestions!

Is your LED staying on steady? Or still blinking? If it's steady, you're probably just in Valet Mode. On your remote, hit lock - unlock - lock if you buttons are seperate. If they're the same button do channel 1 -2 -1. Or you could turn your ignition on, then off, then hit your valet button. Hopefully this helps.

Thank you for your comment, I took the car to a nearby shop and they fixed it easily.