Microtek International — complaint registered but service personnel not visiting and not picking the call

Dear sir/madam,
I have purchased inverter model ebups 1200 v5 on 22.03.2019. The inverter is not working. I have registered complain no. Mjc7337311. But even after 15 days of complain nothing has been done. The service centre and service personnel of your deoghar, jharkhand branch is not picking up the call.
Why company is not replacing the device when it is warranty. The service centre should be blacklisted for their non-cooperative attitude. On 22.08.2019, i received a message from microtec that the complain has been attended. How the technician can close the complain without attending the issue.
You are requested to do the needful at the earliest.