Airtel — airtel outgoing sms not working

Address:

Coimbatore, Tamil Nadu, 641045

Dear sir / madam, i am dr vasudevan. I am a airtel coimbatore prepaid customer. I am not able to send outgoing sms. There is no problem in incoming and outgoing calls. I visited many times in airtel store and have called 121 so many times but the problem still persists. [protected]
Please urgently resolve my issue. I don't know why this is happening. I am really fed up with this issue. It is difficult at times if i can't send sms.

Thanks
Dr vasu