Father in law hit me and mom in law curses me

I had been under mental abuse by in laws since may 2004. I am married since 24-5-2004. Ours was a love marriage but his parents demanded dowry and got our marriage ceremony done like arranged marriage. Post my honey , since then the father in law used abusive, insulting, dominating language on me.. So I had to leave their native and move to my native. They didn't stop their non sense, followed me where ever I went... The mom cries to the son seeking pity and always complaints about me. Two days back I went to native for a function and this father in law hit me on my face and hurted me arms.. This happened in the absense of my husband.. Mom in law curses me and mentions I am not a women. I had tolerated their nonsense for years.. Now I need a legal warning to be issued. I had worked for large corporates and I am a very self disciplined lady. We have two kids and my daughter witnesses all the drama at home..I m going to stay in the native for the rest of my life and I need protection. My husband is good to me and he is also helpless in this matter.. Not just to me, father in law is very abusive, arrogant, speak ill about every family member, highly super egoist person who only ranks himself as human and others as a piece of shit..I need a help for a legal warning letter to be issued.