Get the council involved -if someone new is living there then they probably arent paying additional council tax(the old guy will have single person discount).
The council take ANY form of skipping paying them very seriously - a few years back an ex friend of mine moved her bf in - neighbours reported it and the council watched her flat for a few days and basically said to her we know someone else lives there too and fined her.
This is your proof someone else lives there which you can give to your landlord. Bit of a workaround but hope it can help.
As for him loitering outside your door - phone police non emergency EVERYTIME it happens and tell them hes trying to intimidate you. Should put him off at the very least. |