House alam won't stop! Advice please?

We have just moved into a house with a 'Veritas' R8Plus house alarm; in the middle of the night it went off, we had the apparent code but it was just not working. It has sounded 4 times now in one day; we have no way of turning it off, the police are refusing to help & no one can come out untill monday.

Is there anyway we can di-activate it? we have already removed the fuse but this has made no difference. Thank you.