Have been a VF customer for years. Due to bad service over a year ago they made me a special offer which was a contractual commitment with no end date. When my years contract ended, VF tutued the contract and overcharged me by $312.48 which after a battle got reversed. They then promised to continue what was an agreement anyway in writing, and still continue to stuff up the billing and I cant easily get through apart from the phone where you have to wait for ages for a support member from Philippines to answer. There is an email web interface which is convoluted and does not seem to work reliably.
The only reason I can figure email is so hard to use for Vodafone (and some other Telecos) is that email provides a paper trail in case of TDR disputes later, whereas a telephone call is useful for the recorder only.
If anyone from VF reads this thread, I suggest you have some major problems in your billing department. Definitely, you have problems with communication. Due to this, its caused me several hours of wasted time trying to sort out; its like talking to a bunch of kids who have no idea of what they have done and what they need to do. They give the impression they understand and will sort out then its back to playschool again.
Im not sure if the other Telecos are as erratic as VF, I would hope not!