Contractor not completing building construction

We do not have a formal contract signed but only a draft agreement on the contractor's letterhead. Start date of construction: Feb 2019. Due date for completion: Nov 2019. Now as of Apr 2021 the construction is still not completed. The property & bank loan are in my wife's name. The work has not made much progress after the top roof slab, walls & plastering was completed around Jan 2020. Since then, the contractor, at various times, under the pretext of starting one or the other work (flooring, window grills, frames & panes, wiring, plumbing, gate) asked us & we paid him approx. 90% of the construction cost, but he started some of these & only partially (not fully) completed them after months of follow ups. Bathroom tile work for example took 6 months! (Over the last two & a half years I have had to make thousands of phone calls to him & visited the site at least 500 times to follow up & hoping to see progress.) Each time I speak to him, he gives some excuse & says work would resume next day or next week. Around Aug 2020, he said he could complete all the work in parallel in 3 months by Nov if we gave him the interior work also. Trusting him (& thinking that this additional funds would help complete all the pending work), we paid him. By March 2021, he completed around 80% of the interior work (in a house that has only a few windows and without doors!) & the interior wardrobes & cabinets are lying exposed to dust, winds, dogs, birds & bats, & it took 6 months due to delay in him providing materials. After so much of follow up, just to show that someone is working at the site, he would occasionally have one painter do some wall putty work (for 3 months), & one day each week in the last 4 weeks a welder partially did some window grill work. Each time the contractor says: trust me, I will complete the work in 30 days & he has been saying this for over one & a half years now (post the due date). We have now paid him 93% of the total agreed amount (civil & interior), but at least 20% of the work is still pending. In addition to the money actually paid & the mental agony, our monetary losses during the one & a half years of delay, include one & a half years of interest, additional income tax that had to be paid, huge electricity bills, loss of rental income, all these in my estimation add up to around additional 20% of the total cost. While the quality of construction was good initially, he now has started using sub-standard material for window grills & internal flush doors. We have lost a major part of our life's earnings due to this & don't know what to do. Initially we paid around 5% by cash, the rest of the payments were made either by cheques or online transfer. Though we have been repeatedly asking, he has not given us any bills/receipts. What are the options available to us to get the work completed or to recover the money (20% pending work+20% losses)? Can we file a police complaint, file criminal/civil cases or approach the consumer court?