With AC, you generally have to play HUCA 3-5 times before you get the answer you are looking for.

With HUCA, you always want to be nice and polite with the agent (even if they're having a bad day in Sunny Tampa which is more often than not) so as to ensure you have a blank slate to work with when you call in next. The fact that you argued with an Agent and they notated the file is going to make your schedule change request, much more difficult.

This article on how to play HUCA properly may be of use to you.