A. First you should check on whether this project has been registered under the Real Estate Act,2016 before the Real Estate Regulatory Authority? or any registration application submitted before the same? If yes, get the acknowledgement or registration number for the future correspondence.
B. You can issue a legal notice to the builder to by confirming the flat cancellation and claim the entire amount paid by you along with interest.
C. You may approach either Consumer Forum under the deficiency in the service or Civil Court to recovery of money by initiation summary proceedings in the event no response from the builder side.
D. As far as the recovery of money is concerned that you should submit the documents in connection with the payment transfer details, sale agreements and application form. However, you can approach the court even though you don't have all these documents but at least money transaction receipt or proof is required to recovery or your money.
E. You can recover the damages or compensation other than paid consideration amount on mental torture or agony and the EMI interest is concerned that you should establish your case under the liquidated damages.