I am trying to change the ring delay on my BT Mobile Voicemail from 20 seconds to 30 seconds but it seems to be stuck at 20 seconds. I use the standard MMI code **61*+447953223571*11*30# and it says it has registered but the time stays at 20 seconds.
It used to work that way.
Its normally a setting on the phone itself to do with call forwarding, so it may depend on what type of phone you are using.