Property disputed by the original owners relatives after 10 years, I hold valid legal documents

There are 3 parties to the case. Party A who were the original land owners. Party B who bought it from party A legally and also made a khatha transfer in their name. Party C is me who bought it from party B. I have all the documents related to the sale deed and property was registered into the khatha system in my name as well in year 2004. In the year 2014 an OS was filed in the name of Party A and B by the relatives of Party A. I wasn't made aware of the lawsuit and couldn't respond. The party A's lawyer remained absent in all hearings and the next hearing is in February 2019. The plaintiff erected walls around my and other property holder's plot destroying a temporary structure in my own property. The lawsuit remains inconclusive as nobody was present at the hearing. I suspect that the Party A's relatives have been paid off by a local builder to dispute the land he has no claim to and the said builder wants to acquire the land. Please help me in contemplating the next steps in the said matter. Thanks.