Can I ask for Relieving letter to my second last previous employe

Hello, I have 51 months of work experience till date in IT field and now have got into a reputed MNC before two months. I have shared all my previous work experience letters except for one. Though I have shown my appointment letter and payslips and email text of last working day statement from that employer. I left that company before two years. I worked there for 21 months. From 27th August, 2012-31st May,2014 in two subdivision of contracts. 18 months and then it got renewed. The contract paper was not a stamp paper. It was with company letter head and stamp. I successfully completed my first contract and then got the new one for 18 months, however due to the work scope and salary structure I switched to another job. I served 3 months only from the later contract. Unfortunately my employer wasn't ready to pay my salary and after three months I was paid half the amount (he claimed that I made him loss and it is his wish he won't pay me full). I asked him the release letter, but he arrogantly denied giving it. Now my current company is asking me to produce the relieving letter and relevant experience certificate from that company. I had 21 months of work experience which I don't want to lose anyway. Can you please suggest, what should I do ? Am I eligible to get my experience letter for 21 months ? I had good reputation with my clients on work basis and haven't done any illegal criminal activities. P.S I asked my ex boss for the relieving letter, but he misbehaved and denied to give me. What should I do ? the office was at Kolkata and I work at Bangalore now.