Breach of contract

Dear Sir, I am running a business in Spain using an internet site and a back office that I outsource to a company in New Dehly the scope of work was clear and to be deliver according to a paid amount and calendar. The company did not respect the calendar which was to be deliver in October 2015 arguing they underestimated the work . I accepted in April 2016 to put more money according to some contractual obligation to deliver the job according to hiring skill developper and a new calendar date, The company did not respect it again . The project is now almst one year past deadlines and I ask the company to hand over the source code where they stand now as they are reasonnablly unable to tell me when the job will be finished, They only work from time to time during the day whilst as per contract they were to get one person fill time employ for this only. They re asking for the full blanace to be paid whilst the job is not completed ,. They also blackmail to sell the technology to other company and to make similar website to recoup their loss. I have tried all amicable way to sort but the company refuse and does not respect the contract we had which also involved penalty for delay to which they agree but now refuse to implement. Can someone help ?