in laws

I was married to this family, which lied about the educational qualification and the income of my husband. They were never open about how much he earned until the second month of my marriage, when my husband revealed his income which was much much less than my expectation. I somehow accepted it, and I now I have good relationship with my hubby. Since I am also working, the financial problem is somehow stabilized. However, my in-laws torment me a lot. They accuse me of things like I talk ill about their family and question my values all the time. There were certain things which put me into shock after marriage and I had shared it with some close people. After that they set my sister in law to spy on me all the time. It crossed all barriers when one day she came to my workplace and abused me saying that I had been talking ill about her. Not only that she hit me and spat on me. This situation left me really terrified and I told my father in law and mom in law. But to my surprise they took her side and said that there's no smoke without fire and I did something wrong which compelled my sister in law to take that action. I did not want to prolong that matter for too long, so I decided not too stay in touch with them and concentrate in my work. It did not stop here, she followed me to my mother's house and abused me there too. Now she is getting married and I don't want to participate in any of the celebrations. Am I right to do so?