You can file a complaint against the builder for unfair trade practices and deficiency in services in Consumer Court or RERA seeking complete refund along with interest and compensation for the delay in giving possession by the builder.

You should start by sending a legal notice to them first and give them 7 days to respond. If different to do so you can drag them to court.

For any legal assistance in this matter, feel free to call.

Regards.

1) since builder has failed to deliver possession within stipulated period cancel booking seek refund of money paid by you with interest 

2) if builder fails to refund your money file complaint against builder before RERA and seek refund of money paid by you with interest 

File a RERA complaint claiming compensation for delay or seeking refund of amount paid along the interest.

Alternatively you can also file a consumer complaint in same .

You can also ask for possession, alongwith interest and compensation for the Period of delay.

Interest prayed can be 18-24 % p.a.

Compensation for the mental harassment and agony suffered due to the laches of the builder should be ideally Rs. 10- 15 lakhs.

If you want to get criminal proceedings initiated against the builder you can file complaint to the police against the builder for the offence of criminal breach of trust and cheating under section 406 and 420 of the Indian penal code. 

If police refuse to register FIR, written complaint should be given to senior officials of the police under section 154 (3)CRPC.

However if they also feel to take any action, you can approach magistrate to get FIR registered under section 156 (3) CRPC.

Alternatively, collectively, you along with the other home buyers can give a complaint to the economic offences wing (EOW).

You should seek orders to direct builder to deliver possession of flat within stipulated period 

2) seek orders to direct builder to pay compensation for delay in delivery of possession of flat 

1)You can file criminal complaint u/s 420 

2) You can also file a complaint under Consumer Protection Act or You can also file a civil suit for recovery of said amount , if you don't want to take FLAT.

Dar Cleint,

If you want flat than approach consumer court and RERA, otherwise refund + interest along with compensation.

If you just want refund than file criminal complain u/s 406, 420 IPC.

Refund + 10% interest + compensation.

Whether the construction has been completed or not?

What is the reply from the builder's side about handing over possession?

You may issue a legal notice demanding possession and other requirements to the builder including compensation for the delay in completion of construction.

If you dont get a response or the builder is not complying with the demands made, you may appraoch RERA or consumer forum against the builder for relief and remedy. 

You cannot file any criminal cases for this.

You can issue a legal notice and if the builder is failing to comply with the demands made, you may either approach RERA or consumer forum or even civil court with a suit for specific performance of contract.

Discuss with a local advocate at length and proceed on the advise received.

You can approach the Consumer court for deficiency of service. For criminal case you need to prove there was element of cheating in it

1. As per the information mentioned in the present query, makes it clear that you have been cheated for sure by the well known builder like the above one.
2. I would advice you to go before the RERA and make detail complian agaisnt the builder, first online then following with written complaint.
3. And in the complaint demand for the possession of the flat only as now they are completed or very soon about to be completed.
4. Amd also ask for the interest over the amount you have paid due to the delay in their part, otherwise you must have earned some interest on the amount so paid if invested somewhere.
5. Now a days, RERA is doing something which is very fast and profitable for the aggreived persons.

the builder has defaulted and hence is liable for damages.file a criminal case against them (lodge an FIR) for fraud breach of trust. also, file a complaint against them in the state consumer forum for a refund adding inflation and damages.

regards