Airtel broadband legal notice sent

I have received a legal notice from airtel broadband for non-payment of dues of Rs. 1148 for number 08041533491.

I have sent multiple mails to collections people asking them to send me a bill which would state the month for which I have not paid the amount. I have also stated in one of the mails that I would gladly pay the due if there is any.

Inspite of several mails,I have not got any proper communication from them.

I was a loyal customer of Airtel and had always made the payments at the right time, but this behavior(threatening and filing a case) is just not acceptable or professional.

Even till now I haven't got what I have requested for.

Request you to kindly help me in this regard.