Have a look at this thread and see if it helps
https://community.o2.co.uk/t5/How-to-Guides/All-you-need-to-know-about-O2-Voicemail-901/ba-p/547712
Advice about lengthening ringtone here
Hope that helps and welcome to the forum 
You need to turn off WiFi calling in your MyO2 first
Once that option has been disabled you will be able to use the short codes.
You can enable WiFi calling again if needed afterwards.
@MI5 wrote:You need to turn off WiFi calling in your MyO2 first
Once that option has been disabled you will be able to use the short codes.
You can enable WiFi calling again if needed afterwards.
Exactly that ^^^^^
Enabling wifi calling causes all the above and also simply switching voicemail on or off is impossible. O2 systems are seemingly very limited and unable to cope when new technology is introduced In my opinion a vast amount of money needs to be invested in replacing worn out systems that weren't designed for the modern world.
How are you getting on with this one @jerseymick? Did you find the above suggestions helpful?
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