Rights of old ownership occupier of building to be developed

Sir i had surrender my ownership flat at ghatkopar in 2006 i had two ownership flat of one bedroom hall kitchen of 519.17 sp foot carpet each the builder agreed to give extra 20% so we got 1246 sq ft and we purchased add 95 sq ft so the total area came to 1341 sq foot it was one full block instead of two register block one in my self and my brother name . The builder agreed to pay rent for for 18 months @ 30 per sq ft after 24 months if he could not give possesion he agreed to pay penalty for rs 200 per day above 30 per sqft if the project is not completed within 30 months the project stands cancelled and holders of flat will be free to take possession of their incomplete flats and will complete balance work at the cost of builder . The builder increase rent and gave possession in year june 2014 after 8 eight years and also did not pay rent for period apr 2013 to june 2014 and after that i thought of taking possession in june 2014 and while taking possesion he took undertaking from me that he has cleared all dues from me and their nothing recoverable from him , as I wanted possession and he was not paying rent I had no other option but to take possession and give undertaking . Now after taking possession he did not allow me to carry out work like breaking flower bed etc but instead told me if i pay him 10 to 15 laks i would allow him and also give in writing for extra area approx 125 sqfoot officially but i told he i will see to it later on . Now during the meeting with builder he told all the occupants of new building whose agreement were before approx 2012 to pay for funjible f s i . Now through my relative I have come to know that extre funjible f s i given to builder is not chargeableto old tenents holders . Also he promise to give parking in 2006 but know he has not alloted fix parking to us instead to some old holders he has given or sold parking below stilt or basement , Even to new buyers he has alloted or sold two fix parkings in stilt or basements and problem of parking in open spaceis occuring during days and night and he has closed some basement parking by applying chains so nobody can use it how can parking problem can be solved Also suggest for funjible f s i and parking space and for rent which he has not paid for 15 months ,my name kishoor shah