Problem In Adding Phone Account In Bsnl Site To Pay Bills Online?

I am trying to add my landline phone in bsnl side to pay the bills but i am facing a problem.
For adding the number, i have given
1) user id
2) circle as Tamil Nadu
3) Phone Number
4) Account Number
But there is another entry called SSA/STD.
I couldn’t find any entry for both SSA and STD for chennai.
Kindly guide me on how to add my details for chennai.in bsnl site .
Thanks in advance.