Legal Heir versus beneficiary claim based on unregistered will

My Uncle (Father's Younger Brother) and his wife (Aunty) died without any issues. therefore my Father became the legal Heir for both of them and a decree was obtained from the Hon Court. Meanwhile relatives from my aunt claim that they are the beneficiaries of all the Assets of my Uncle and Aunt based on an unregistered Will. Even after 18 years they have not taken any steps to Probate the Will by approaching the appropriate Probate Court. Registration of the said Will is also pending with Sub-registrar after we filed objection regarding my aunt's signature in the Will. We have filed a suit for recovery of the Property from my aunt's relatives and there also they mentioned about the Will, but did not come forward to provide additional evidence reg the Will. their motto seems to delay as much as possible the closing of the case. Now when the Add Dist Judge is about to deliver his judgement on the recovery suit, they have filed an objection in the Hight court with CRP. what should be done when we know that they are totally abusing the Process of Law .