Marriage cancellation

I was engaged with someone on June month and the marriage is arranged on November month.. but now he is always dominating me . groom and his mother always hurting us with their words . they are giving mind torture to me and my family members.. then I addressed his issue to him.. he is not ready to accept it and he gave me a choice to cancel the marriage. later on I decided to cancel the marriage with my parents knowledge.. he also accepted for it and now wants to cancel the wedding .. but now his family members creating a problem .. we are willing to return their gifts but they are not ready to accept it. they demanding money for those gifts..they are blackmailing us like If we didn't give money instead of those gifts then they won't sign on the written statement of marriage cancellation.. I don't know what to do now.. please advise...