No voicemail unless data turned on?

[Marco123]

My 6S is on O2 network and unless I have my 3G data turned on, I can't retrieve my voicemail.
When data is off there is always a red dot on the green phone icon and only goes away when I turn mobile data on.
I didn't realise I needed mobile data to retrieve my voicemail on the UK O2 network, is this true?

 

[arefbe]

I've experienced that, too. I'm on AT&T, though. I also sometimes don't get all my messages unless I turn data on as well.

 

[chabig]

Visual voicemail IS data. It always has been. If you don't want to use visual voicemail, you can always call your own phone number and retrieve voicemail serially the old fashioned way.