Airtel — No assistance post payment

Greetings,

I wanted to buy a new broadband connection and I decided to go with the brand name of Airtel. I thought the process and everything will be quick and smooth but I was surprized. The Sales person(SP) contacted me once I showed my interest in the new connection. He made a call and promised a lot of things and I thought fine. So I made the payment of Rs 3532 to Airtel for a 6 month subscription and once the payment was done, the SP took a side step. The technician told me only half of he promised speed can be provided. I thought as the payment was already made, let me just go ahead with it but then the technician told me that they will have to relogin the details.
Post that I am just chasing the SP and the technician. Payment is done and Airtel has got what they wanted. They are least bothered about the service leave alone the post sales service.
I tried to contact the customer care on numerous customer care nos but to no vain.
Airtel has disappointed me to the core.
Proof of payment attached.

Regards