1. If the completed work is hardly 45% then why did you make payment of approx 90% amount? Anyway, serve him a legal notice throuft counsel to complete his part of commitment as per the agreement to bound him for the legal battle

You should talk to builder and send  legal notice to him stating all your grievances. In case he does not respond then file a complaint against him in the RERA tribunal immediately.

It is necessary to peruse terms of contract awarded by you 

2) there must be clause that of work is not completed within stipulated period contractor would be liable to pay penalty for delay in completion of work 

3) youcan terminate the contract and claim damages from the contractor for poor quality of work done and for failure to complete it within stipulated period 

Sue him in the consumer court. This should be preceded by a legal notice. This, for you now you are advised to send him a legal notice after consulting a local lawyer.

1. You can file a Police FIR, requesting investigation and charge-sheet, for offences like Cheating, Intimidation, Fraud, Breach of Trust, Mischief etc.... against the person, supported with all relevant supporting Documents & Witnesses.

2. IF the Police does not take action, THEN you can file private criminal case u/s 156(3) Cr.P.C., in the local Magistrates court, seeking directions to the Police to investigate and file charge sheet. The said Person may come down for settlement.

You committed a mistake of making advance payment. File FIR of cheating but if FIR will register or not- Rare possibility as matter is of civil nature.

Have to file civil suit for direction to complete the construction as decided under the agreement.

If you have an agreement in writing then you issue a legal notice to the contractor bout it and demand compensation for the delay in completion of the construction.

If the quality of work is not satisfactory and not conforming to the contract conditions, you may drag him to consumer forum seeking compensation as well as the damages.

he can be sued for breach of contract and you can  claim damages, you can very well approach Consumer Forum for compensation..

See you can file a consumer complaint seeking direction to complete work and compensation for low quality work and mental harassment.

1. Send a legal notice to contractor for completing the work with in next 3 months and quality of work should be good. 

2. If you don't want to continue with his contract then send him a legal notice for stopping the work and refund of money with in 15 days of time. 

3. If he refuse to give satisfactory reply then you should file a suit for Breach of contract and temporary injunctions against contractor and claim refund of money along with interest and compensation.

Dear Sir,

It is better to get issue a legal notice and after that go for consumer court and claim damages by contractor.

You can file complaint before consumer court for deficiency of service against him