Dispute with contractor regarding incomplete house.

My wife an agreement with contractor to construct a house with labour and material. Total 10 month he have to complete the house but starting a work he work very slow and material used in house is very low quality. After poor quality work we stop the contractor for other work. At present condition of incomplete house is that only a brisk structure was stand with first floor. When we say to contractor to raise the bill for that work so we should give the rest of amount and terminate the agreement. The contractor said verbally that total 55% work was completed and the amount was around 15 lak was due. In advance we pay him 6.50 lak already. I ask the contractor that if that work is 55% than what about the rest of work that include in and out plaster ,all electric ,sanitation and plumbing internal and outdoor fittings. Frames of door and window and fitting of door and window. Marbel fitting,color in and out and other minor civil work. He did not gave me satisfactory answer. We call him two times for settlement that reasonable amount that was actual costs we want to pay . According the government approved house valuer also submitted his report that the all brisk work construction total amount was only 6.20 lak only. My question is that how to sort this problem either court or consumer . I already launch a grivenance in local police.