Do I need to hire lawyer for legal notice after illegal termination?

Can I send legal notice to my employer without a lawyer? I have been working with a franchise owner of reputed tech institute for 5 months. I have been told to resign out of nowhere after unfair vocal termination. I haven't received my final settlement of salary and incentives even after 3+ months after termination. I tried connecting through calls, texts and emails but no appropriate response has been received. I even told them that I would seek legal help, but still, they are saying that the company is financially broke so it won't affect them. What is the best course of action? Should I send a proper legal notice again or file a complaint in district court directly? Do I need a lawyer for it or If I do it without a lawyer will it be effective? Also, how much would it cost me ( time and money) to go through all these procedures?