Kitchen Window closed with a plywood by neighbour

Sir, Along with our kitchen window our neighbours Open terrace is attached. They have closed the terrace and converted it into a room with brick wall on one side and sliding window on the other side. third side is an opproach to it from their kitchen and the forth side being our kitchen wall. As an when we cook the air is getting circulated in our room only. We have fitted exhaust fan on our kitchen window. They ordered us to remove the exhaust fan in a threatening manner. Society gave a solution to put the ducting which was not accepted by them. Later when our house was locked they covered the kitchen window with a plywood from their side. Now it has been more than 20 days they are not removing it. We have given letter to Muncipality, first reminder also given. Till now no action has been take by them. Further we like to share that since our neighbour was ex-police officer he threatened to hit with police stick. We would like to have some legal advise regarding 1. Closed window for more than 20 days. 2. Threatened to hit with police stick. 3. Till now no action from muncipality. 4. Can we put a legal case on our neighbour. Please do suggest us what further action can be taken. Awaiting your reply eagerly.