I am in possession,flat buyer agreement

I purchased a shop from Mr.A in resale who had paid 90% of the payment to builder & balance amount was paid by me to the builder. Mr.A had signed a allotment of office/shop space agreement dated 12.02.1973 with the builder and I agreed to abide by the terms and conditions of this flat buyer's agreement and the allotment was approved by the builder. The clause no. 6 stated that flat buyers agreement will be executed in companys standard form. Clause no.12. Stated that the conveyance of the building will be executed in the name of a limited company or a corporate body/Co-operative society to be decided by the promoters. The builder issued me certificate dated 27.01.1978 that since I have cleared all outstanding dues the temporary possession of the shop given to me should be treated as permanent. Builder also give me letter that the shop is owned by me and possession was handed over to me on 1st dec 1977 and I had given affidavit to MCD that I have purchased shop from builder and I have been paying its house tax. Last bill received from builder for ground rent,replacement fund was dated 31.01.2012. The shop buyer agreement which was to be executed in builders standard form was not executed. I am in possession. Kindly inform also keeping in view sec.4(2) of The Delhi Apartment ownership act and Real estate act.