What followed was the type of typical red tape scenario that I had rather expected earlier. Apparently after two days of getting to actually do the sort of thing I am paid to do it was time for the system to shoot me in the foot. I called the help desk, who forwarded me to someone else, who then said that no, the help desk is supposed to handle that, call them back and ask for an admin. This I did, and was told they would put a ticket in. Then I waited. After an hour or so of waiting I got antsy and called back. We are a busy group and work, and there was stuff I needed to do. When I called the help desk back I discovered that my ticket had been sitting in limbo because they couldn't do that. I was told to call a different help desk. I did that, and another ticket was opened. Some time later I was called back and asked some questions. Some time after that I was called back again and told that they couldn't help me because my account was privileged, I needed to call this other number that he was going to give me. He gave me the new number, which I recognized as the help desk number. When I protested that I'd called them three times already to no avail, he suggested that I ask for a manager.
Instead of asking for the help desk manager I talked to my manager. As is so often the case, it is much more useful to know who to talk to, and my manager almost always knows. I ended up calling this guy I worked on a project with, who reactivated my account for me, or at least I assume he has because by that time it was time to leave.