Cheating by contractor

We started renovation work with a contractor on a bulk amount to be paid. The amount was 11lakhs which included main jobs (written) plus some unwritten odd jobs. The time of delivery promised was one month if we weren't living in the property or two months or little earlier if we weren't moving out. We chose the second option. Initial two weeks work was fast, quality wasn't upto the mark though. After which the work got very very slow. Whenever I would question he would say, because you are living here people aren't getting movement. Whereas, we shifted to just one room, a bathroom and kitchen. I gave them three bedrooms, gallery, two bathrooms, four balconies and drawing room to work in. I even allowed work on Sundays and till late evenings 11pm on some days as we have no restrictions in our society. In the beginning we were promised that two bedrooms will be readied and given to us after primer and first coat of paint. Which hasn't happened till date. (Work started on 8th Aug 17 & today is 22 Sept 17). Finally I could not allow them further entry as we didn't have anywhere to go. The work is moving at a snail's pace. He cheated us on quality of veneer also, now he is asking extra money for everything wanting us to pay him 10 lakhs by 1st of Oct 17 & pay the rest amount of 3-4 lakhs more later (the final amount was 11 lakhs). With absolutely no extra work over and above what was discussed and agreed upon. He says ceiling pop has gone beyond estimated budget and will incur additional 70,000 or above cost, similarly everything where he can show that he has put in extra effort and where extra money can be extracted he is trying to magnify that and portray to us. The actual work done till now is somewhere around 2 lakhs and we have paid 4.8 lakhs but he wants 2.5 today and another 2.5 by 30th or 1st to move work at a very fast pace (which I haven't witnessed happening).