Airtel — message sending failed. customer care completely clueless

I have not been able to send sms from my airtel number for over a month now.
After calling the service center multiple times on 27th nov between 8pm and 10:30 pm, all i got was incomplete and repetitive information.
With the help of google i was able to find the steps to set the message service centre number but i get this error now : setting interrogation failed.
The airtel "executives" have no solution and all i do is spend money on taking to customer care. Also, if i ask to talk to a supervisor, i am put on an indefinite hold.
Apart from the inability of airtel to provide basic services like sms, having a incompetent customer care division who trick customers by putting their calls on hold and ignore them until they hang up by themselves is completely unacceptable.
I am looking for an immediate resolution of my problem which is due to improper settings provided/made by airtel.