[Resolved]  Airtel — Fraud call possibly forging Airtel and Airtel is not bothered

I had enquired for the conversion of an Airtel prepaid number to postpaid over email, to which I had got a reply. Sometime later I received a call from a person (a mobile number) claiming to be an Airtel executive and telling me about a plan especially for me (which was not mentioned in the mail I received in reply to my query). It was a 399 plan which included 600 local+std minutes, 200 local+national SMS and 1 GB 3g/4g data after consumption of which I will have unlimited 2g. I found the plan to be a good option and said yes. He asked me my address and told that an executive will visit me to collect my documents and Rs 250 activation fee, to which I agreed. He informed that this 250 will be refunded in the 3rd bill that will be generated. That was the conversation I had with him. It occurred to me after sometime that he has not asked for the number I want to convert from prepaid to postpaid, and I had not specified the number even in the mail I wrote to Airtel. That made me doubt on the authenticity of the call. So, I wrote a mail to Airtel providing all details and asked if this was a genuine call from one of their representatives. I also called the customer care because that person had scheduled a visit in the evening and I wanted to be sure before I handed over the documents and money to him.
And to my surprise, I got the most non chalant replies on all my attempts - no reply to email, one of the executives on call was clueless, another said that this is not their department.
I am shocked to know that there is probably a person forging to be from Airtel and collecting money and documents fraudently and Airtel is least concerned about these activities. I am not saying it was definitely a fraud call because I don't have proper grounds to claim that. But isn't it the responsibility of Airtel to investigate and clarify if a customer is vigilant enough to notice it? Another pointer is - I received a call from another mobile number today morning for the same reason. I postponed the visit because of my doubts and told this guy that I will inform when I will be available by contacting customer care. He said I don't need to call customer care, I can call him directly and inform. I have not seen such visits being scheduled directly by Airtel executives on mobile numbers in the past.
The least I expect from Airtel is to atleast confirm the authenticity of these calls. But there has been no action/reply at all.