Engagement Cancellation

Hi, We found the match through Matrimonial site and both the families liked each other and even Myself and girl liked me and we got engaged last year in May 2017.Now when we wanted to fix the date for marriage girls grandfather passed away. As rituals are there in Hindu religion.We waited for 2 months and when again discussion started for fixing marriage date unfortunately girls aunt passed away. It was very unfortunate for girls family. So again deciding on marriage date was postponed. In between my family consulted Pandit and was informed the Kundalis has some Nadi Dosh and girl is Manglik so they to do puja before marriage. We communicated the same to girls family. Now girls father in front of both the families said they will nt do the Puja and wants to cancel the engagement. Our family still thought lets give some time and due to heated arguments girl father took the discussion. We wanted to calm down things.But girls mother who is also a Mahila Mandal leader in the local area went to our relatives (Grandmother, uncle and auntie) house and told they want to cancel and doesn't want to continue with a local leader.But called us and told we should discuss once again.So both the families agreed. Now we got to know about girls mom going to our relatives and informing them about cancel.When asked she first denied and later said she has nt done anything wrong. Now also she wants to cancel. Post which my family is really very upset and doesn't want to continue with marriage. We called but girls parent's doesn't come on the phone or call back.Girls daughter answered and we told we want to discuss she denied to give the phn to her mom.We have sent a letter asking them to official cancel as we foresee threat to our family and family reputation.Its been 2 months they have nt responsed to the letter nor even called.We have the Acknowledment from courier company they have received the letter. Kindly suggest how do we come out of it. As we our looking for a different match and feel girls mom might create trouble as she has a lot of influences in the area with politicians. Please let m know if you need any further details. Regards, Mallesh Sunchu