If you have not filed complaint before NCDRC you can file complaint against builder before RERA and seek orders to direct builder to refund your money with interest as he has failed to complete the project on time and notice has been issued by DHFL for confiscation of flats 

2) in alternative as financial creditor you can file insolvency petition against builder before NCLT 

NCLT is fast remedy. Buyer is financial creditor have prior claim than bank. File petition before NCLT for initiation of insolvency process. 

The NCLT proceedings can be initiated if the status of the company is active in case you have already filed a consumer complaint then in that case it is better to proceed with them at this stage.

You can opt for nclt or consumer court. Both options are good. Nclt is speedier than consumer court but has fees for the same

Yes NCLT proceedings is the right choice for recovery of your advance payments by declaring you as creditors and beginning of liquidation of assets of builder for payment of loans and credits. 

Application for initiating insolvency resolution process or liquidation of corporate debtor shall be filed before the NCLT having jurisdiction over the place where registered office of the corporate entity is situated.

Under Section 7 - Financial creditor can, either alone or jointly with others, file an application
before NCLT for initiating IRP when default has occurred.
Default includes a default in respect of a financial debt owned not only to the applicant
financial creditor but to any other financial creditor of the corporate debtor.

Condition Precedent for Filing Petition :
Though Code does not specifically says so but from the scheme of the Code, it is apparent that the petition under Section 7 and 8 of the Code shall not be maintainable if there is a slightest dispute or doubt about the payability of the amount claimed either by (i)Financial Creditor or by (ii)Operational Creditor.
The above provisions has been held in the case law Annapurna Infrastructure Pvt. Ltd and Ors. Vs. Soril Infra Resources Ltd.
MANU/NC/0190/2017 where the petition is rejected since the amount claimed was in dispute due to a counter claim.
(A) Amount claimed should not time-barred;  Indian Turpentine & Resin Co Ltd Vs. Pioneer
Consolidated Co of India Ltd 1988 (64) Company Cases 169
(B) The amount should not be in dispute:
I) Madhusudar Gordhandas & Co Vs. Madhu Woollen Industries (P) Ltd 1972 (42) Company Cases 125 : AIR 1971 SC 2600.
II) Sir Shadilal Enterprises Vs. Coop Co Ltd 2001(103) Company Cases 863 (All)

Under Section 7 of Code, Financial Creditor shall make an application in Form No.6 along with the
following documents:
a)A record of default
b)Evidence of default
c)Other records
d)Letters exchanged between the parties
e)A Statement of Account showing the financial debt payment by the Corporate Debtor – preferably certified by CA or other practicing professional;
f)Legal Notice sent by the Financial Creditor
g)Reply, if any, received from the Corporate Debtor
h)Board Resolution authorizing person who signed
petition
i)Evidence of Fees of Rs.25,000 – The DD in then name of The Pay & Accounts Officer, Ministry of
Corporate Affairs;
j) Copy of Memorandum & Article of Corporate Debtor;
k) Consent of Insolvency Resolution Professional
l) Application for interim stay;
Legally speaking Section 7 does not postulate service of notice upon the Corporate Debtor. However, it is advisable for the financial creditor to serve a notice upon the corporate debtor setting out therein the
(i)amount of loan or credit facilities availed provided
(ii) how much amount has been repaid

iii) how much is the balance left

(iv) accrued interest thereon
(v)any other admissible amount

(vi) aggregate
amount payable by the corporate debtor;