My Company is not giving experience letter after poor performance termination.

Hi, I was working for a Tech Company since 7 Months and Now they asked for Security cheque worth three months of salary as commitment that I will not leave the company for next two years & Also they stopped my last month salary for 15 days in order to get the cheque from me. I denied by saying that there was no conditions or commitment for any period written in my offer letter. So, they terminated my employment by giving the reason of "Poor Performance"(I did not resigned) and asked me to come for exit procedure documentation and salary cheque collection. On meeting They denied me to give experience certificate and relieving letter. Because of they were not completing the documentation work I also denied to sign the confidentiality undertaking document provided by them to get my cheque. In result, I have to went back without salary cheque as well as experience certificate and relieving letter. They are clearly want me to suffer without any reason. I am just a fresher candidate and starting my career with good hope. Kindly, Guide me if there is any law in the labor court or civil court to get my certificates and salary. In evidence I am having call recording of the conversation with company owner in which they ask for the commitment cheque and denying to provide my salary as well as documents.