Veritas R8. Resetting?

The electricity in our area went off for two hours, when it went off our alarm went off, I put my code in but the alarm would not stop, I put the code in again but it still would not stop. I opened the main box and dissconected the battery and the alarm was silenced. When the electricity came back on the alarm went off again, I entered my code but the alarm would not stop, I reconnected the battery and closed the door of the main box but that made no difference, finally I have had to disconect the battery and the mains circuit on which the alarm is fed to silence the alarm. Can you please help?