We had a power cut, the outside light keeps flashing?

We recently had a power cut, the alarm went off, it has since stopped, but the outside blue alarm light keeps flashing.
I have read the manual and it says to enter engineer codes on the keypad. I've gone to the keypad, it's lit but its not responding to anything being entered.
I've tried ringing the helpline, but apparently they are too busy at this moment to answer my call (obviously because these alarms are crap and everyone is calling). Has or does anyone know how to rectify this problem please? Many thanks