Employer is not paying my salary

I have been working in a IT company in Noida since November 2017, when I joined the company they told me that I'll be on evaluation period for one month and after that I'll get the offer letter. I got the offer letter after one month which only contained information regarding my salary package, there's no description about the notice period or anything. The company has paid my salary till March 2018(which is also not complete Rs. 5,000 are still remaining), and after that I stopped receiving my salary. Then from May, they told me to either work from home or from the company's owner flat. I told them I will work from home. But still I haven't received my salary the employer assured me several times that he will credit my salary within 2-3 days but could never do so. Then on May 25th I spoke to the employer/owner of the company that I won't be able to continue like this and will be joining another company soon. He didn't say anything about resignation and notice period at that time. But now when he knows that I stopped working for him he is blaming me that I haven't told him earlier regarding the job switch though I have informed him on 25th May. He is refusing to pay me my salary which is due from April 2018 also I have the company's laptop, and he is threating me to return their laptop otherwise he will take legal action against me. I'm pretty sure if I return his laptop he will never pay my salary. Please help me what should I do.