Tata Docomo — not able to send sms

Address:

Bangalore, Karnataka, 560064

Hello!
I am kiran kumar ([protected]) using the tata docomo prepaid sim since 2014.
I m not able to send sms. Each time i call the customer care, they say there is no issue and refresh the sms centre no as [protected] and then restart the phone which i have done some 4 to 5 times but still i m not able to send sms.

Kindly resolve this issue or give me a solution for this.