Mental Harassment by Brother in law and parents in law

Good morning all, Me and my husband moved to Australia 3 years ago and are now permanent residents here. My brother in law came to Australia on PR as well later in 2015 and was going through his second divorce. we supported him at that time and kept him with us for couple of months. during this time period he started a small business with us in Australia which we had to close due to failure and intellectual issues between the partners means me, my husband and my brother in law. Since this business venture has closed . my in laws mainly my brother in law have started troubling me and my husband mentally. My brother in law went back to India only after living with us for 2 months and started living with my parents in law. there were issues and arguments going about the financial loss in business and it was getting heated up. so as a solution we thought we will invite our parents in law to Australia and explain everything to them so that they can resolve this with in the family. But opposite to that, they had their own complaints about their money demands from us. they had a list as follows: we should return them the money that they spent on our wedding and our migration. we should send them gifts on every occasion. we shouldn't be thinking of buying anything for us in Australia rather send them any spare money after our basic expenses. we should be working day and night so that we can earn more and send them money. me particularly can't financially support my maternal family at all. The basic reason of this hatred is I sent money for my fathers medical treatment around 3.5 lacs 2 years ago when he had his By pass surgery. Now they are trying to pull every person in my maternal family and social circle into this and sending vague legal notices to my relatives to harass them. My Father on law said himself"we know we wont get anything out of this but at least you and your family will be mentally harassed" My husband stands with me and supports me, he is witness that I haven't done or thought anything bad about my in laws. we are so scared of them that we cant even come to India to see my family. Please advise if I can stop all this to happen, it is very stressful, sometimes we think the only resolution is divorce for the betterment of us both and my family. These all situations are leading to problems between me and my husband.