Microtek International — Paid for AMC but not registered in their system - No one is ready to respond/resolve the issue

I paid for AMC (Received receipt Rs. 799 - Receipt no 467214) on 21st December 2021 to take care of my Microteck inverters (SEBZ 900). When am trying to register a compliant about the fault, i understood from the service desk team that my AMC is not reflecting in the system. They have provided me another number ([protected]) to raise another complaint. I tried this number many time but no response and even if it connects they disconnect in between. This is really frustrating. Looks like the service is very bad.