How do I get miles redeposited for a flight on UA?

I needed to cancel, I spoke with the call center. It was they day before the flight, so I wanted to make sure it got cancelled. She told me she could cancel the flight but she couldn't redeposit miles or issue a refund. She said more than that but honestly I couldn't understand what she was saying.

I get that there is a $25 fee which I am happy to pay, but I have no idea how to get the miles redeposited. I only paid about $5 in taxes so I'm not all that concerned about getting that refunded, but I would like the miles redeposited.