Building contractor Cheated

I have agreement for construction of building with construction contractor for G+2 @ 1,343/sft in Dec 2020 full of 49lakhs. Initially work has been carried out as per schedule, later he said construct G+3(G+1 for 1350 and 2&3F for 1250) whole project built up 4700sft offered and agreed for 57 lakhs(for that he gave letterhead of his company in Feb2022 from his maii id mentioned as "Final Bill") later he said he face loss so i increased one more room 10*10 = 200 sft for 2.5 lakhs. After receiving this amount, contractor was not reachable/picking calls. After few days, when i got him on his mobile, he says he has lost money & working with lot of delays and discontinuty & has also shifted his office at last traced the residence visited and requested 5 times and then started work for sometime. Now remaining 4Lakhs work is pending at site, i have a recent written saying only pending work is 2.5Lakhs from him saying and he mentioned he said will finsih by 5/7/2022 balance mentioned as 1 lakh with this sign When i approached police to lodge complaint, they said you resolve the issue outside amicably and at police station he is claiming he wants now more amount as per agreement 1343*4930 which comes 66lakhs he demanded 8Lakhs, now he is saying that he will go to court and file a case against on me for that amount. so far i paid 58lakhs and all online transaction details. If I file a case how long it will take, Can I invest and complete the leftover work and acquire position. what probable actions can he take on me and what I can. please suggest.