You were able to log in right ? And it says No record ? Check if previous month's usage details are visible. May be some updating on portal and get ok in a day or two. Did you try register at selfcare.edc portal ? It allows registration for those who use data.bsnl.in too. I have both. May be they have shifted your usage details to selfcare.edc. Check that too.
Which plan do you use ? Use Shaplus, Networx or Bitmeter to keep a check on your usage. Networx allow monitoring router and syncs with other PCs using Networx in the same network.