Contractor is threatening

Dear Sir/Madam, We had appointed a local contractor to build my home. He was my friend so we did not do any agreement for construction. He orally told me that he will complete home in 6 months. I gave all money as per our oral contract after 11 months he did no complete the work. My house construction contractor has cheated us and asking for more money without completing the work and stopping the work for more than 1 month stating that we should pay him more money He is also not giving us the bills or receipts for material he has brought for house construction but still claiming for the money. He is now threatening us that if we do not pay him , he will not allow us to engage any other contractor for the further work. He is also not continuing the work and asking for more money. This is leading to loss as the material lying in the site is going waste such as sand and cement due to rains. He is threatening to workers of other contractor I have appointed for my compound work. Now nobody is ready to work. Please advice me what to do in such case. I have made mistake by not doing any agreement. Please advice. Thank you