Alas, I have the same issue with my phone, but I am hoping it is something that can be fixed with a iOS update.
I also had an issue where my ringtone didn't play and the one playing was a lot softer than what my settings was. Downloading my old purchased tones and manually changing the settings resolved the issue for me.
But since my upgrade on friday, I have not had internet access via 3G/4G. Changed the APN settings and restarted the phone, but no luck as yet. Guess I'll have to phone vodacom.