BB Torch :: Keep Say That ID Or Password Is Attempt Wrong?

I'm using maxis prepaid network. Since last 2 months, every time I renew my Blackberry Internet Service (BIS) and I restart my blackberry, I TOTALLY cannot get into it. It will ask me to sign in my blackberry ID. The problem is, every time I sign in my mail and password, I still cannot get through, it keep say that my ID or password is attempt wrong.But if I sign in using PC, laptop, there's no problem.I've problem with this before, but the supplier said, I need to re-format my blackberry. If every month I need to re-format suddenly like that, my document inside blackberry were gone, and I need to re-save it..