veritas8 alarm?

hi can someone help while i was on holiday my son was looking after my house he went to check the house and put the code in but the alarm went off. he retryed many times but nothing on coming back from my hols the alarm light outside is still flashing and it won;t let me reset it . the alarm isn't going off but when we walk in the hallway the pir picks us up and starts to bleep and the panel says unset and this is flashing can someone pls help thanks Bev :-)