Hi Please someone help me!!!

I have a VW Bora 1.6SE 1999 and the alarm keeps randomly going off.
I took it to the place i brought it and they said that they removed the sensors and cleaned them all and it seams to be ok. However it went off last night twice and i was woundering if you can turn the seneitvity down on it/ and where to do it?

Please help!!!!!

Thanks


Azzaone