Dominating and harrassment to me and my mom by my wife and inlaws

I did an arranged marriage. I already told her father and her family that we are not as rich as them. she must not go to work as I have shop and she can help me as my mom has got old, she has to cook food for three of us, we have maid for washing clothes and utensils. but she and her family members accepted all the conditions. after 15 days of our marriage she started harrasing my mom mentally by not talkin to her, not listening, stopped doing some of the works telling lies that her health is not well . sleeping for long time, talking with her mom all the days. when I , my sis and my mom asked her why she is doing this she told that she doesnot have any thing in her mind. due to this behaviour I called her mom and dad but they humiliated me by saying that we will take our daughter as well as we will also kill your whole family. I have that much powe. my pregnant sister got scared and fell ill. they want that we must allow her to work and say that she may also get boar after 2 mnths and stop wrking, she will not cook food, will not assist us in our shop and my mom must do all the work. she shared all such things with her mom but not with me even after asking several times. she also told my sis that she has done mistake by getting married with me. even I dont want to get along with her but she and her father wants us to accept her and they say tht I have to go to there house, stay there,etc. but they are very bad ppl and I dont want this girl coz they are dominating us which I not acceptable. How can I get rid of her. My all property is on my moms name and it her self purchased property. If i file for divorce they may trouble my mom or try to kill us. Any other way so that I can get rid of this family? plz suggest