Maybe try going to main office at 13th street and R
If you're in the Sacramento area you can go in person to the business office at the 13th and R light rail station.
If it is a refund amount for a single fare and you don't remember the PIN, you haven't much chance of getting money back. I experienced lots of double and triple charges when I used their app and was not pleased about it. Eventually I got of the app out of frustration. Maybe you'll have better luck through perseverance.
Sorry I have no idea
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