How to stop voicemail service on iPhone - Reliance GSM Prepaid

[rajivunique 6]

Hi Friends,

I am using a RGSM (also named as SMART prepaid connection in W.B Circle) in iPhone 4S. The Issue I am facing is if my phone is off or not reachable, All the callers goes to a voice mail system where in there is no message or nothing , it just charges the caller as any other normal call.

I complained to 198 but as expected they dont have any answer, no help recieved, Finally some one is saying that I need to check with my handset service center.

This only happens with Reliance GSM, I have used AIRTEL and DOCOMO with the same phone and this doesn't happen.

Any idea gurus ???

Thanks.