engagement broke by a boy as he had an affair

sir, My cousin was engaged to a guy last month.on third day of engagement his mother called and informed to girls mother that the there is roumer about boys character so we will cancel the negagement..girls parents were worried and they shouted at her...later boy's father called girls parents and said that boy has a affair with another girl so he is not willing to marry my cousin...We have spent nearly 1lac to the enagegemnt...they demanded dowry for rupess 4 lacs cash...5 cents palce which is nearly 10-15 lacks and 80 grams of gold...Girls parents accepted for everything...the conversaton for 4 lakhs cash was on phone....After they said they want to cancel the marriage...gilrs parents called boys parents to solve this prblm peacefully...They are not willing to come come and boys mother is threatening that she will remove all the jobs of girls family....and they are not even feeling sorry for whta they did...Boys mother said initially that boy liked the girl very much and he will shift his job place to the girls job place...and he is very much intrested to marry....boy is not even responding to the calls of girls parents... girls family is a middle class family 1 lac is very huge amount for them..not only this they gave money for ring suit etc on the engagement day ...they kepy many hopes abt this marriage....is there any way to proceed legally...Please give some suggesion....