bis or internet problem please help

Hi.. ppl
I m from India and I m using IDEA sim card
its a GSM sim
I m using blackberry 8830 WE and my internet keep on disconnecting at any time ... And start working my itself ... I just called the idea consumer care ppl and they told me that there is no problem with there service ... Every thing is working fine from there side ... can anyone please tell me what is the problem ??
and ya its just not 1 sim which is making this problem .. i have tried Vodafone sim and reliance sim also but these sim's are making the same problem ... :(

Have you tried reloading the OS, or updating it (if any are available?)

Posted from my CrackBerry at wapforums.crackberry.com

Yes when i brought this phone it was on 4.2 but now i have updates to 4.5.0.127
one time i have reloaded the same os also ... i clean my bb with BBSAK then reloaded the os with bb desktop software
and one more thing ... beside this ever thing is wotrking fine but on top of it it say Activation Required and when i dile ##000000 it say invalid password ...