ADA vs individual issue not resolved after 15 years

Dear Members, There is a case which was filed in the year 2000 by my grandmother against the most corrupt ADA-Allahabad Dev. Authority. Let me give a brief about the situation- A flat (cost 25000/-) was allotted by ADA in 1987 and my Grandmother who paid all the installments plus more in advance without fail till 2000 the actual maturity date on papers. When in 2000 she asked ADA to do final dues calculations and register flat in her favor. She got a reply from ADA that Rs 44000/- is due which she need to pay first for flat registry. When she contacted ADA in this regard she was told to pay 10000/- as bribe to settle down the issue. She decided to file a case in Allahabad DC against ADA. A hell lot of legal paper work were done, too many judges came and go, hundreds of meaningless dates were allotted and a no. of lawyers we hired but no result. Sadly the lady passed in 2004 and my father started fighting the case and in the same context he met the ADA top officials and explain them the matter, Luckily a lady officer heard him and passed an order that all said dues are cleared, only pay the registry charges and get it done. Now when my father asked to start the registration process in his favor, he got a reply from ADA that first to take back the case and pay the cost of court case and proceedings to ADA, only then they can move application further. Please suggest what steps we should take to close the matter asap. Right now the case is in inactive mode for years.