Has anyone else had the issue of missing calls and texts while the iPhone was locked?

I have noticed occasionally while my iPhone is locked and sitting next to a speaker i will hear the incoming calls static via the speaker but the phone won't ring. I'll unlock the phone and the time will go a bit crazy for a second (like it was lagging behind and quickly count up to the current time) then a missed call would pop up.

I'm worried that if i give this back to Optus to fix ill be without a phone for over a week and once its at Apple they might not be able to replicate the problem as it's intermittent and might only happen once every couple of days.

Any input would help on what i should do.

im with optus and telstra (personal iphone and work) and both do not have any issues sending or receiving calls.
Have you tried putting the phone into airplane mode for 10 secs then turning it off?

I'm sure its not a problem from Optus but rather my phone. As soon as I unlock the phone it sorts itself out and im sweet for a couple days again.

hi people

im new to this forum.
dont know this is the right place to post me question.
i bought a 16gb 3g iphone phone ebay but the guy didnt know the phone was locked to optus or vodafone or telstra. now i tried to put optus and vodafone sim card but it only have the icon like a usb connection and itunes. my question is how do i know which provider is my iphone belong? bcause i would like to unlock it. could someone help me please


cheers