I am not a new user. I was having the 59 series IP earlier. Recently, it was changed to 112 series.
Today I logged in directly to *bbservice.bsnl.in using Firefox. I entered the portal id which was given for my connection and my password. It showed me the page of some person in ginde colony,tilakwadi,bm, karnataka. I was able to see his usage. The most shocking thing is that it looks like I can change his password for portal id or broadband user id. When I chose the option to change the password, it asked just for the new password, didn't ask for the existing password.
Even after signing out, if I login again, I was taken to this guys page. That's a first. Last time, I was taken to 2/3 different persons pages and finally got mine.
One thing I am not sure is that I have my connection at Kerala. I was checking this from my office in Bengaluru. May be that has some relation. Anyway this a very serious problem.