My sisters cellphone (some 3G Samsung model) and my friends cellphone (Sony Ericson W950) have both had trouble sending and receiving text messages and getting calls. The text messages only sometimes go through and when text messages are recieved, all the messages received, are received at once.
Today, I was trying to help my friend sort out this problem with his phone, when I discovered that my phone (Nokia N95) was set to GSM only (not UMTS (3G) and GSM). I then changed the settings on his phone to GSM only and his phone started working normally again. The text messages sent the first time he sent them and he recieved them when I sent them. He could also now receive calls.
I would say that there is some problem with Vodafone's 3G network at the moment, and that if you are also experienceing these kind of problems, try switching your phone onto GSM only. It has helped in these two cases

Hope this helps for you, cheers Matt