For Uncompleted Flat and Delay Rera or NCLT or Self Buid

I booked a flat in 2014. The builder has build my tower almost 90% but then saying complete your flat yourself and doing some amount reimbursement. In other work is not even done 30-50% so they all are thinking to go to NCLT but for my case all buyer of my tower are confuse that we should go with them for NCLT as : 1. Ist option Builder is giving that complete remaining flat yourself and reimburse around 50% by them. Take possession without OC , CC It do not seem a good idea that no car parking , no amenities have been developed till now. 2. On basis of above point 1 should I file a case in NCLT or in RERA 3. I suppose to get my flat by DEC 2018 but builder just sent a fit out mail without CC/OC in Feb 2020 and saying will not pay penalty beyond that, is that right ? 4. For NCLT only this is enough that builder complete remaining 10% flat or also in NCLT I can get compensation/ completion for remaining amenities like car parking , no park but I paid for car parking ? 5. In my case are there any chances of getting refund with interest in NCLT and compensation? 6. Is my case even valid in NCLT or not ? Someone please reply early as we all want to decide and file case in next 2-3 days only