we have accenta g3 model but the tamper lights keeps flahing tamper light w?

we have accenta g3 model but the tamper lights keeps flahing tamper light we thinks when christmas went up they knocked the alarm box outside we check it and its on ok check pirs they are fine been told we have to put in engineer code but dont know it (company gone out of business) nothing on instruction paper work can you please help me
07956 228972
kind regards
bob