iPhone showing voicemail icon when there is none?

[iMacMart]

Guys

My 3Gs shows voice mails icon even when there is none? I have to call
my voice mail to hear her say there is none before it goes? Anyone else get this?

EDIT: Not sure if this should have been in software actually?

 

[geekyEd]

Find somewhere with a signal to get your messages.

 

[iMacMart]

Find somewhere with a signal to get your messages.

OK so yesterday at the time of the screen shots I had no signal, but this isn't the first time I've had this all other times I've had full signal hence starting this thread

Second screen shot shows voice-mail icon and no messages?

Thanks