Claim and reimbursement issue with company as channel partner

Dear sir We are doing corporate services as per company guideline. We were associated with BTI Payments Ltd in their division INDIA ONE ATM on service channel partner contract for five years. This agreement implemented from September 2015 on ward for five years. But they have paid us till july 2016 and stop our payment further without any confirmation and mail us that they appointed some one else to do the work assigned to us. So we ask them without any mail communication or any written information why this is happen. One of the employee has taken his personal interest with some body and start paying them whether we are already working for three month but when our claim not received on monthly basis so we will have to stop working and asking for my payment then they said only security deposit will be refunded. so we fight for our monthly claim. In this regard they given written termination letted on 25th of February 2019 . So we are asking our office expenses till termination and our claim for those three month. For that we have lodged complain on My grievance portal Govt of India. They transfer case to Labor commissioner, Bihar. Now I want to take legal action against company. How can we proceed.