Flight cancelled and stranded. Is schengen area no longer 90 days in 180 rolling? (More info)

(Last one got removed sorry, I posted it in a panic with not enough info)

I visit europe every couple of months. I stay for a little less than 90 days. I go back to america for 90. Then visit europe again. It's never been a problem

I booked a new flight a month or two ago to go to europe again. Booked with united, connection with swiss. Left my state to another state on united. Went to the swiss counter to depart to europe. They told me it's not a 180 \*rolling\* day period and that I would be deported if I went, so they cancelled the flight.

They said no laws have changed recently. I have multiple passport stamps showing me entering and leaving europe within the rolling 180 day window just fine. They repeatedly told me I was wrong and they wouldn't keep the flight

Had to call united. Very helpful person on the phone but seemed confused by it all. Getting me back home. But I still don't know why this happened.

Edit: They helped me finally get a new flight for 5 or so hours later than the initial flight, after hours of effort