Unless Vodafone have seriously improved from about 3 years ago, I'm surprised they have any customers left.
Here in Newcastle, disconnected calls were common, 3G impossible to use any time from the minute you wake up to the minute you go to sleep (but its fine to use then because everyone is asleep), and once people discovered you could use 2G as a (poor) substitute, that service went to shit as well.
Wasn't just me either, all my VF using colleagues were affected, and it was a common issue throughout the area. From talking to those foolish people who are still with them based on their constant promises to do something about it, it's still a bag of wank.
Every other provider has provided a MUCH better service.
I think they only seem to survive because most businesses seem to default to Vodafone.