Yes. You can opt out of Auto-buy at any time before 12:00 AM Pacific Time (PT) on the release date of the upcoming volume or chapter.
Once 12:00 AM Pacific Time (PT) on the release date has passed, the Auto-buy purchase will be processed automatically and cannot be canceled.
You can turn off Auto-buy from:
– The Series page, or
– Library → Upcoming → Auto-buying Series
Where can I purchase Japanese eBooks?