FOX channel was owned by Disney, it closed down. This affected Sky TV, Virgin and NOW, everyone who had a paid TV package was affected.
It was announced and evern on the channel itself stated it was closing at the end of June.
Not all content on FOX will be on Disney+ as some of it is owned and distributed by CBS. Likes of Bull and NCIS.
FYI that I do not work for NOW, I am simply a NOW customer trying to help I am a Community Contributor This means that I know a lot about the service and like you I am still a customer. For any account issues you’ll need to contact staff via customer support.