Company is delaying FNF.

Hello sir, I had worked in Franciscan Solutions PVT LTD. Greater NOIDA for 2 years 1 Month from Oct 2016 till Nov 2018. I resigned from the organization because the company was delaying salary every month and I didn't find any better future there. So I resigned and served almost 21 days of the notice period. My resignation was accepted by my project manager and at the end of my last working I collected my relevant document from that organization and for my FNF payment I was told that I would get my FNF amount after 45 days so waited and when waiting period was over I approached to my previous office and there was some ceremony was going on so HR asked me to call him after two days so I called him but he didn't respond. After a number of attempts I received my half of payment on Jan 30, 2019, after 3 months and for rest of payment I was given Post Dated Cheque for the date May 20, 2019. When I deposited my cheque on May 20, 2019, I got to know that payment was stopped on that cheque. I was not intimated about this. I am average and only earning male in my family and that's what I had told them so many times but they didn't even bother. When I approach their office, they make me to wait for a long time. When I call them they just try to convince me that I would soon get my money but after this signed cheque stop payment issue occurred. I just fail to understand what to do because now again I have to track them every single day by calling them again and again. Again I have to plead them again and again for my own money. Should I approach to a local lawyer for notice or should I file a case against them in the local police station? Please suggest.