Marriage is cancelled after engagement

Hi All, I'm the Groom, my marriage is cancelled after 2 months of engagement, reason for this is girl has health issues like Thyroid and Cyst problems (Which was conveyed only to me by the girl after engagement, not by her parents or relatives to me or to my parents till now.) Girl also told that, if I tell this issues to someone with either of our parents, she told that she will commit suicide. I'm ok with her health issues, I had a plan to take care of her health after marriage by having regular treatments. So I have just proceeded this proposal. But girl uses to fight with me from starting for each and everything that I use to talk, even for silly things. After 2 months of marriage her parents called me and my parents to talk about marriage. So we went to their home, but thy have threatened us and they are ordering me and my family to change ourselves to match with there daughters behaviour. We told that we cannot able to change ourselves to match the girl behaviour, since we are not expecting anything from girl's side (we din't demanded for any dowry in form of gold, cash, property or any other way), on saying this girl has told that, she wanted to cancel the proposal if we are not changing ourselves (she did also told that she is not interested to marry me many times even for silly fights and we clearly came to know that her parents are forcing her to marry me before this decision was taken), on hearing this we came out of their house by telling that we are also not ok to proceed with this girl, since she is not interested and cancelled it. They did engagement in a party hall (which cost Rs. 25000 with photography Rs. 15000 and food Rs. 230 per head - This has been enquired directly from the respective vendors last week). As a part of tradition we have gifted to girl 5.2 soverign of gold and Rs. 50000 for saree and Rs. 50000 as gift. But now they are demanding us that they have spent 4l for engagement, even after this was cancelled by her daughter. Request you to help me by giving the valuable suggestions on this. P.S. we are comfortable to pay half of the money from actual expenses.