Airtel — Unbundling from Airtel Black - no proper billing details and delay

I have Airtel Black plan with Airtel with registered number xxx. I have been trying to unbundle it from last 2 days but not getting any proper response. Various billing amount is provided with no proper justification and clarification or breakdown. After paying amount when I called again I was asked to pay a new amount again. 5 mins job o[censored]nbundling has already taken 2 days. I have been trying to reach manager but they are also not available. What kind of black service is this?
This is the most pathetic service I have received.
Also if I mail they are just asking to register email instead of looking into the issue.