I hired a contractor to do my house renovation. He committed a gross technical negligence. He promised to rectify. Now he is saying he might or might not rectify it because its not in contract. He gave substandard work on plastering works hiring his casual workers to handle this specialised job. There are deep long cracks on plastering works now and he claims thats normal. He is aggressive and reacts with hostility when i ask him work site related work. Twice he wrote via sms asking me to terminate his contract. He didn't ask for extension of time despite expiry of completion date. Kept me in dark on completion date. His verbal promises are forgotten and he looks into the loopholes of the contract to deceive me after 6 months into contract. Help me!