[Resolved]  BSNL home 250 plan — USERNAME and PASSWORD are invalid

Its been just one month since i started using BSNL Home250 plan. For the first 3 days it worked perfectly and i was very happy. But suddenly on the 4th day, woooopssss, it stopped working. Since then, its showing error 691 i.e. "either User name or Password is invalid". I have lodged a complaint thrice but nothing seems to be working. Customer care people are so pathetic that you dont even feel like talking to them. Customer care executives themselves dont have any idea about my Internet problem.

I dont know what i should do to get it on track once again.