Legal information about what can be done if the employer is rejecting my demand of relieving letter?

Details of the issue: I worked at an organization for 16 months between June 2013 to November 2014. I had to leave the organization due to unavoidable circumstances (my marriage and other issues). I joined an another organization in last month of 2014, when they asked for relieving letter, I explained them the situation and they understood my point. I was advised to send a letter through post containing my resignation and last day of work., which I sent and they cleared me for hiring. After 1.5 years, I joined another organization and the same issue happened as I didn't had relieving letter or exp letter from the first organization. I tried to contact them again but no help. But this time, during the background verification process, the first organization gave a very negative feedback about me. This made the new organization's HR think and we all sat together and sorted out the issue. I explained them the situation and showed them the documents of employment, salary slips, appreciation and promotion letter. After a lot of discussion they understood me and found me right and offered me job. Now comes the problem - I again resigned and joined a new firm after good 1.5 years and again I needed the relieving letter from that very first organization. This time I went on to meet the man in charge there and he misbehaved me. He said that he can not help in any case and will not go back four years and give me any letter. Even I pleaded and cried but no help and he even threatened me that he will ask the security to take me out if I didn't leave. Now as I have joined this new company and its been 3 months already and their background verification result just came and as expected it was negative from that very first employer, other than him, everything was perfect. The head of that first organization has again given a very bad feedback of me and asked the verifier to not to get in touch again. The HRs of new employer are considering his words as final and not considering my words, proofs and letters. These people are asking me to provide relieving letter by Monday or else I will be fired. I am married man with a kid and only provider to the family. I need to know my rights in this case. Thanks