Experience Letter

I was working with a company in Chandigarh and after four months of my service, I got another job in Gurgaon and they wanted me to join as earliest as possible as well as I needed urgent leaves. So I went to my COO and discussed with him regarding the leaves and urgent joining in the new company and requested him to reduce my notice period. He started talking rudely and told my that he'll increase my notice period to compensate for leaves. I told him that I won't be able to increase the notice period. He refused again. I again went next day to talk to him and offered to do the knowledge transfer, but he again talked rudely and started putting allegations on me. Feeling insulted, I told him that I won't be coming here from next working day. After three working days, I got a call from CEO and HR and on the mail they told me to the knowledge transfer and some help in projects and in return they'll give me my salary and experience letter and I agreed to help. After helping them, they transferred the salary to my account but now they are refusing to give me my experience letter. Please advice me what to do now. I am thinking of going to labour court but I want to know the odds of losing the case and the procedure of filling the case.