veritas r8?

Hello
Ive just bought a house with veritas alarm.Everything was sound till my wife switch the power off by mistake.Switch it on again and alarm start playing up.It looks like it tries to arm itself.when no one is in the range of the sensors its armed then activate and waking up all neighbours.i cant enter my code because for some reason 0 and reset buttons stopped working.I found in the internet that might be dead battery.help me please