Airtel — Non installation is xstream fibre connection even after paying the amount

I booked for Airtel xsrtream fibre new connection 799 plan on 29th sept 2020
In my premises at Raman street, T Nagar Chennai
On 30 th sep Airtel person came and said that DP box has to be provided and it is not his department
Since then nothing has happened till today
On complaining to customer care, but they are sending repair team to rectify the fault in the connection which is yet to be provided. are sendingand also to support team of Airtel they are sending proof of payment made by me
On talking to various Airtel officials I am only getting evading replies,
No one is providing higher official’s contact number
I have exahusted all avenues and landed nowhere and my money is stuck up
They do not pickup the phone and when they pick up they get irritated
I donot know what to do to resolve the problem