I'd let it drop, mysefl. Your route required two 500's and that is what (in the end) they took. Asking for a complimentary upgrade for the inconvenience is, in my opinion, out of line. Yes, the agent was rude, but hey, it happens to all of us from time to time. I personally don't expect UA to comp me something when they are, nor do I expect a formal apology from the agent or the company, since it is (for me) such a rare event. I chalk it up to "Stuff Happens".