how do i re-program my veritasR8 plus alarm?

How can i re-program my Veritas alarm after having to reset it with factory code 4321.
We had to switch off power to the whole house and alarm when connected back up would not work, alarms sounded and no code would stop them. It had to be left with no battery as we could not find the reset pins in the main box. An electrician then had to set it back to factory settings of 4321.
Non of my zones work. When i use part 1 for example it is supposed to omit landing. Then when i go downstairs i have 20 secs or so of beeps to enter code to turn alarm off. However, the alarm sounds once i have reached the bottom of the stairs, as soon as i enter an alarmed area.
Also when on "full" and i come back into house the alarm sounds as soon as i open external door and i have no time to enter code.
I have tried using factory code and i have also tried my original code too,as i can change code okay.
Please help i am climbing the walls as i have tried everything in the user manual.
Thanks