Yes that’s all correct. I bought the new $280 ticket via the UA app. thanks for condensing!

Did the airport agent cancel the old ticket, did you tell the agent you made other arrangements or did the automatic UA system cancel the original ticket? - - the UA system canceled the original ticket, once I noticed my boarding pass disappeared, I went to agent for help and told her I’d bought back up ticket and now my boarding pass was gone. She confirmed my original seat had been canceled.

Did you ever ask for the old ticket to be restored and the newer ticket canceled before taking the flight? — yes, while I didn’t say “restore”, I did ask the agent if I could go back to original flight and get a refund. In her defense, she was quite busy. She walked to a different gate desk to ask a question about how to do my ticket and then told me she was newly back at work. I was also quite stressed and tired, not thinking clearly. I asked her several times about a refund because I found her answers confusing. She kept mentioning miles and I kept repeating the $280. There were also people waiting behind me, so I didn’t want to take too long. She assured me it was all taken care of, no problem. Again, I learned a lot from this but is there any way UA will refund or credit the $280?