Almost every single thing that can be done in verizon's site returns an error and suggests calling instead. Not many people seem to complain about it here though, so it's either me the only one having problems or that people don't care?. When things worked 1 or 2 years ago it used to be great not having to call to change small things; I don't like contacting customer service by phone.
I think the problem is that verizon consists of a mismash of different companies. Bell Atlantic, NYNEX, GTE and others.
They must have different computer systems and the webpage can't work with all the different systems. My mother has comcast at her house, that webpage is worse than verizon's. Dish Network seemed to have a pretty good webpage but they don't offer as much stuff as verizon.
Things are always changing in the world of computers. In addition to the mishmash of companies/systems, think of how many computers they must be using to do all those things and in so many different states.
There are several threads located elsewhere on the forums talking about issues. Some people have been successfull calling the ECenter number. Search ECenter 877 and you should find one of those threads.