I played this game - https://online-go.com/game/14636096 - and I kept passing until my opponent also passed, but during the stone removal phase it didn’t show his dead stones as removed. I didn’t really care much because I was winning without them so I accepted the result. Then it returned to the game again but would jump back to the stone removal again even though I didn’t pass. It did this over and over again. Sometimes I would need to pass again. Sometimes I played some more stones hoping that would help. Not sure if my opponent was doing something to cause it, but eventually I reported the game to a moderator and resigned.
You did exactly the right thing by calling a Mod and just resigning. While the available solutions aren’t perfect, they are sufficient to ensure that good experiences vastly outnumber bad ones.
