Airtel — replacement sim activation

This is regarding the activation of my new SIM card which is a replacement sim as I got my number blocked a week ago.
On Monday, 30th July, I purchased a new sim from a local retailer. Airtel's support staff kept on saying that the SIM card will be activated in another 24hrs, 4hrs, 1 hour and so on; which never happened. Several calls were made by us during the period but to no avail. They kept on convincing the same till Friday, 3rd August; after which I was told to purchase another new replacement SIM from their Airtel store, specifically.
There were no Airtel stores in close proximity, however, I took the pain to travel some distance to visit the Airtel store for the same. I got a new sim and completed the formalities there, after which I was assured that the sim will activate in another 4 hours, which of course never happened.
I have called their support staffs innumerable times since then but still they failed to get my sim activated.
Even now, I've been convinced that in an hour they'll get it done.
They have no idea about the troubles we are facing. Contacting the customer care service for infinite number of times and still not getting the issue resolved.
Because of their careless attitude, all my important calls and messages I've been missing since a week, which is causing a lot of inconvenience.
Apart from all of it, I am unable to understand what is so difficult in activating a mere SIM card rather why are they making it sound so impossible?
They better get this issue resolved and get my number activated right now, and if not, then I'm done with Airtel.