Dispute Property In Delhi (DDA Flat)

My mother had purchased a DDA flat in 1994 from property agent, but could not it get registered or any other written paper proof regarding being was purchased by us but we have physical possession since that date to till now & and staying with family as present without any objection was raised by the owner. My mother filed a court case against property agent in 2005/ IPC act 451/324 however due to some circumstances she did compromise and closed to case front of an honorable judge in Hight Court. after closing the case she hasn't received any paper as she had been promised by property in court and a few days later the agent disappeared. She's paying house tax s .electicity water bill since 2004 (register with my mother's name) she made her voter card in 1996 on the same address. Also, she has other id profs. Aadhar, Passport, old ration-card too. Now after a long year almost 15 years later .we found that property agent. Now my mother wants to re-open the case.