I have a 1999'p38 range rover 4.6 hse passenger door lock stuck?

On my range rover p38'as i was unlocking it with the fob some one pulled the passenger door handle so,know rest of car unlocks and locks but passenger door lock wont work wont unlock but also after 24 hours when you un lock the doors they re lock straight away but can still,use and says alarm on display
Any ideas cheers david