Airtel — Network broadband issue

I have been facing network issues with my broadband. Not getting appropriate speeds due to which I had raised a request on 26th September to change my plan and it's been almost 19 days till now I have not received any call from airtel. I have reached multiple times to customer care, the only answer I received was to wait for another 12 hours somebody will reach out to you. No one has reached out to me till date even after the case is escalated to back end team. I am not sure what should be next action steps.