Maan hani dawa

Hi, my name is Prashant, I reside in Bhilai city of  Chhattisgarh state, India, on one side of my house there is a gali of 10 feet between our house boundraywall and neighbour's house buundarywall. And on the adjacent side boundarywall 10 feet is empty space along the street road, we have constructed a small garage for keeping a cow, but since cow's death that garage is not in use. But my neighbour is alway threatening to demolish that garage even though it not in their side, it is along the road that too between road and my boundarywall, now that neighbour has extended his house 3 feet on the gali side and when today we also called lobours to extend our 3 feet, he and his crooked son started querreling and using very abusive language, that first demolish the garage then only i will let you do work on this side otherwise i will hit the labours. We said let Nagar-Nigam demolish it if they think so, but that neighbour kepton using abusive words and pressurising to demolish that garage. Other neighbours are also not so supportive. What can be done legally, and what should i do:-

(1) Should I file a FIR against him in my area Police Station.

(2) Should I talk to a laywer for filing a defamation case against them.

Please suggest I am fedup with this behaviour, but i want to do something now, so that a message may be sent to them that we are not the silent listeners.....

Regards....