I had a terrible experience with the Sify Salesperson last week

Hi,
I had a terrible experience with the Sify Salesperson last week. My apartment has around 40 connections of Sify already, but despite that this salesperson has not been able to followup on his commitments on installation. On top of it, when I was upset about the initial lethargy that I faced and I talked tough to him, the way he responded was too arrogant for a Sales person. Typical behaviour of a monopoly, but unacceptable from a Private Company. I would like to escalate this matter. Do you know of any Senior Management emails/phones who I can complain to?
Regards
Jacob