Disputed 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 flat (house) was purchased by us but we have physical possession since that date to till now & and staying with family till now no 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 but she haven't received paper as she had been promised by property agent and a few days later he disappeared. she's paying house tax .electicity b, water bills ( register with my mother name) she made her voter card in 1996 on the same address. after 15 years we found that property agent. now my mother wants to re-open the case or suggest us what we can do it in this matter. what are the chances to get our property pepper or suggest us so can start the process to get back our property paper