Blackmailing marrige

Respected sir, meri friend problem face kar rahi hai, uske parents ne uski shadi bua (father' sister) ke ladke se fix kiyi thi, o dono bat karte the kuch din tak sab thik tha kuch din bad meri friend ko pata chala ki uske pahile bahut ladkiyo se relation the isliye usne ye rista todne ki koshish kar rahi thi, lekin usne ye bat apne parents se nahi batayi kuch din bad usne apne mobile se use msg kiya muze ye relation nahi chahiye, fir ladke ne planning ki use ek bar milna hai bolke bulaya aur blackmail karke temple me shadi ki koi witness nahi the, photo liye dono ke sath me, ladki ne sare document galat sign kar diye lekin thumb sahi lagaya, document me ek 100 rs ka bond paper tha. use ne use daraya ki kisi ko mat bolo ladki ne sari bat ghar me parents ko boli parents ne koi legal action nahi li kyo ki ladka unke sister ka tha. uno ne use samjaya o man nai raha hai. use sare relatives ko call karke ladki burai ki, ladki meri friend bahut jyada depress hai, kuch din bad unone police case karne ki koshish ki police ne unki complaint nahi li, uske parents ne marrige ke bare me pata kiya koi court me register nahi hai aur ladki ke koi documents uske pass nahi hai, pls ab kya karna chahiye, ladki ka koi relation nahi hai uske sath physical koi relation nahi aur sath me ek sath nahi rahe ek bhi din. pls advice