Hi Rene, I've just posted a thread about me and my dad getting calls failed for every call on Vodafone UK on 4.2.1 (iphone 4).
It's getting beyond annoying now that we are both loosing business. Please see the link and let me know what you think.
Little bit of back ground info on us... we are both IT Technicians so have alot of tech knowledge and have tried EVERYTHING.
Any help is appreciated!