I'm with Vodafone and my experience with billing has been very much a miss. That part of the business must be based overseas and has taken a little longer than I would've expected.
However recently with issues with a Fibre speed upgrade, which caused all sorts of other problems with our TV subscription was handled very well. With staff members involved going well beyond what I'd expect from any company. The levels of communication with how the process was going was far better than I had experienced with other telecommunication companies.