13-08-2018 19:02 - edited 13-08-2018 19:21
Did anyone get to the bottom of this?
I had the same problem when I was with EE, they couldn't increase the ring time to anything more than 20 seconds either.
I think I might have found a way around it though, I'm currently on a Samsung S9+ if anyone is interested.
The way I found to have Wifi and 4G calling AND have 30 seconds of ring time was as follows...
Log in to my O2 and disable wifi and 4g calling.
Reboot your phone, check that the wifi calling icon is missing and if you place a test call it drops from 4G to 3G/2G.
Once you're sure that Wifi/4G calling has been removed do the following...
Open your dialler and key ##002# SEND to cancel all current diverts.
Check the diverts for each one have been cancelled by dialling *#67# SEND, *#61# SEND and *#62# SEND. On each reply it should say there's no diverts active.
Dial the following...
**61*plus 44, seven eight zero two zero nine one nine zero one*11*30# SEND
Dial *#61# and it should come up with a reply similar to the picture attached.
Activate the rest of the diverts such as busy and unreachable by dialling...
You can then check each one to make sure it's active by *#62# and *#67#
Log back in to my o2 and reactivate Wifi and 4G calling.
Reboot your phone, ensure the Wifi and 4G calling icons are back if applicable, do a test call by checking if your phone falls back to 3G/2G, if not then you're ready to go. You can check again by dialling *#61# SEND to ensure that the 30 seconds is still showing.
Hope this helps, I know it's a long winded way around it, but it's definitely working for me now and has been for a few days.
on 21-11-2018 14:10
OnePlus 6 (O2 & Sfr), Z3 Tablet (Three UK), iPhone7 (EE)