UK Electronics Repair Questions? Ask a Technician ASAP
This sounds like a faulty battery, does the keypad otherwise light up and work? If not then remove the power and battery and then repower with mains only (leave the battery off for now) and if everything is ok then you will need to get a new battery
It sounds like the power cut has damaged the alarm controller... If the keypad no longer responds correctly with mains on and battery off then this indicates a problem in the controller itself, you may be able to claim the repair on your insurance as it is likely you may need a new controller...
If you refit the battery and close the control box does the keypad work properly?
I am not part of the billing system, contact***@******.*** and include a link to this page and they will sort this out for you... I am sorry this has happened but the site will promptly refund any errors...
How did you get on with the alarm?