I need to set up call divert (**21*phone number#SEND) and I'm having the dreaded "Connection problem or invalid MMI code" issue that I've seen discussed in a couple of threads on here (the consensus from other threads appears to be that the problem is resolved when WiFi/4G calling is disabled on the account).
The problem I'm having is that no one from O2 seems to be able to actually switch this off any more! (and I can't do it from my phone - I don't the option in the settings). I've spoken to both customer services and technical support, a 'form' has been sent through to the 'Guru' (network services) team, I've waited the 48 hours required, and nothing. Customer services has advised me there's nothing they can do apart from raise another 'form' (it sounds like a form = a service ticket), and cross fingers as apparently there's no way for anyone in the call centre to get through to anyone in that team any more.
I'm very frustrated at the moment - call divert is a very basic feature that I didn't build in extra time in my plans to get fixed this slowly. Has anyone successfully found a way through this process/problem, or knows a good way of spurring the 'Guru' team into action?
To rub in the wound, with Vodafone (the mobile provider I did expect problems with), it worked first time!
You actually need wifi calling OFF to send MMI codes across the network.
It's another of those "things" with O2.
I know that this is an old thread but I thought that I would resurrect it just to say thank you!
My phone has been stuck on call divert for just about a week now. I tried the usual stuff (dial 1760, dial ##002#, soft reset, switch off WIFI calling, a prayer to God etc) but nothing worked. I called customer services to help and they filled out a security form to cancel voicemail and told me to wait 24 hours for some sort of magic to occur. None did, it didn't work.
Then I stumbled across this thread and ##21# finally, finally worked! So once again thank you. You're a star!