Sale agreement

Dear Sir/Madam. I would like to get few information, recently I have purchased a property. Now we have noticed during construction there is case on a property, one of the person from other city called MR.X has made the sale agreement for 20 Lakhs and the remaining 80 lakhs will be given in other 24months, now the period is lapsed. However the person has filed the case on vendors that vendors are not coming forward to receive the remaining money. Meanwhile a vendor as sold the property to MR.A later court as passed on the compromise decree in 2014 and it was said to pay the remaining amount to court on or before 31Nov 2015, however the person failed to pay the amount to the court. By seeing the court decree we have purchased the site from MR.A. Now we have realized that MR.X has filed one more case on 1st Feb 2015, stating vendors are not ready to collect the cash. Now they are not letting us to construct the site. For your reference kindly find the OS no 1229 of 2015. Please advise us on this.