I'm a recently hired assistant professor at a small teaching university. The department head has been successful in dramatically increasing student enrollment, such that our department is viewed almost as keeping the faculty and university afloat (and the department head is VERY highly regarded on campus). The department head is close to the office admin (he treats her like a daughter and she acts like a quasi assistant department head - approving new classes and setting the schedule, for example).
When I was newly arrived I foolishly agreed to a scheme proposed by the office admin where an instructor would develop a course that I would teach next term. After not hearing anything for quite some time, I checked up on the course progress and it turned out the instructor didn't intend to give me anything related to the course until the first day of class (when I was suppose to be teaching it that day). There was some back and forth and eventually the instructor committed to me that they would get me the course by the end of November. The end of November came and went, and when I asked about it I was assured I'd get it Friday. Friday came and went and on Monday I was assured I'd get it the next day, which I didn't. When I saw what she had made available to me on Tuesday, it turned out she had barely started working on the course.
I went to talk to the office admin (who had set the whole thing up and been acting as an intermediary) and told her the course wasn't near completion and at this point I wouldn't be able to teach it. She told me to talk to the department head. Previously I had wanted to involve him and she had told me repeatedly not to. As I left she began heckling me (telling me the instructor had been very busy with other projects), when I tried to respond to her, she cut me off and told me to talk about it with the department head. Again, as I turned to leave, she started heckling me (asking me why I expected the course so early) and told me I hadn't treated the instructor fairly.
I told her that I felt she and the instructor hadn't treated me fairly, and that they had thrown me under the bus as a newly arrived member of the department. She went NUTS. She started screaming, saying she didn't appreciate being accused of throwing someone under the bus and that I'd thrown her under the bus. She said she wouldn't accept being talked to that way and she would be complaining to the department head and her staff supervisor (which I found out later she did) and she slammed her door on me (I began walking away when she started screaming).
The department head came to my office and told me I wouldn't have to teach the course and that I'd be assigned another section of a class I'd already taught (which was fine with me and one of the solutions I'd previously tried to suggest). He didn't seem to want to hear anything else and just wanted it wrapped up as quickly as possible. I had written up my understanding of what had happened, which I gave him a hardcopy of (he didn't want to take it) and sent to him via e-mail. In the e-mail I asked to have another member of the faculty present at any meeting on the issue.
I think the existence of an e-mailed copy of the incident caught the department head's attention, as he then (later in the day) wanted to set up another meeting (but made it very clear no other faculty members could participate). At the meeting he again seemed very eager to brush things under the rug. I said that I wanted to be sure this didn't happen again, which he said he had no control over. I also said that I felt this shouldn't have happened and I wanted it to be treated seriously if it happened again, which he agreed to. I told him that the office admin had threatened to make complaints against me (which he said I didn't have to worry about). I asked him if I should be going on record about what had happen to HR and he told me not to. He told me that if I couldn't resolve things with him, the Dean was the next person to talk to and that under no circumstances would he involve other faculty members in meetings of this nature.
I talked to one of the senior faculty members and he told me that the department head has deliberately concentrated authority with himself and delegates things to the admin (so that another faculty member doesn't have control over them). He also said that he definitely didn't chastise the admin (and probably didn't even say anything to her).
I've thought about this situation and how unpleasant things will be in the department going forward. Since the new term has started I've been receiving dirty looks from the office admin whenever I've been forced into contact with her (I've been avoiding it as much as possible). I'm basically at the point where being in this department for the next 5 years leading up to tenure is pretty depressing (to say nothing of the idea of spending the rest of my career there) and am planning to set up another meeting with the department head.
Basically, I want to express that I think there's still a problem and I'm prepared to resign if that's the only solution. I obviously will make my resignation effective at the end of the school year (I won't leave them in the lurch). I'll tell him I wanted to give him another chance to solve the problem (and also feel that I should talk to the dean and HR before I tender my resignation so that they aren't blindsided - I want to let my department head know I'll be talking to them so he isn't surprised).
I'd be willing to stay if it was clearly expressed to the office admin that her actions were inappropriate. At this point I think that would require something along the lines of an official rebuke that would be put in her employment file.
For what it's worth, my teaching evaluations (from the one term I've been here) are very high and my research profile is probably the best in the department. I have a large number of other options for employment (which will probably be outside of academia). I don't need references or anything, so while I realize I'm "burning a bridge", that won't cause me any problems.
Does anyone have any advice on how I should move forward? I'd certainly understand anyone who thought I was "making a mountain out of a molehill", but this is still bothering me more than a month after the fact.
Sorry for the length, I thought it was important to include all relevant details.
EDIT: A moderator asked me below what I want from people who respond. I'm hoping for tactical advice (the best way to achieve an official rebuke, if it's impossible, advice on how to move past it). I'd also appreciate opinions on whether or not I'm justified being upset by the situation.