Different subject but a takeover should always be fully defaulted and reprogrammed to prevent issues like this.plus you dont know whats sparre off etc.
however timstool?
Sounds like it was a takeover without defaulting panel (dangerous and shouldn't be done Imo)
As it wasn't defaulted the comms programming is still calling home itself giving the previous provider with full remote access.
Only way to remove the password is to default.
Then only you can access etc
it was in alarm and you have silenced it?
have you pressed reset?
assuming you dont care about it and not serviced etc?
do your neighbours a favour and decomission it before it causes you a problem
alternatively if your asking for the burglar code that kills a system,obviously it doesn't exist outside of diy grade systems