Regarding your first comment, please read this from the Frequently Asked Questions (
lichess.org/faq#rating-refund):
"One minute after a player is marked, their 40 latest rated games in the last 3 days are taken. If you are their opponent in those games, you lost rating (because of a loss or a draw), and your rating was not provisional, you get a rating refund. The refund is capped based on your peak rating and your rating progress after the game. (For example, if your rating greatly increased after those games, you might get no refund or only a partial refund.) A refund will never exceed 150 points."
In short, perhaps your game wasn't in their last 40 or your rating had recovered sufficiently since your loss.
Regarding your second comment, please read the Lichess Terms of Service (
lichess.org/terms-of-service). FYI — "I have questions" leaves no doubt you are publicly suggesting a player could be cheating. Lichess really doesn't like that:
"The public accusation of a player suspected of cheating is not tolerated, and is bad sportsmanship. If you suspect a user of cheating, please report them via the icon on their profile page, or from the report page."
lichess.org/report