If you have an unwanted calendar appearing in Cupla, here's what to do:
Tap More.
Tap Calendar Settings.
Tap Calendar Connections.
Untick any calendars you do not want synced to Cupla.
If you cannot see the calendar in the list, scroll all the way to the bottom — it may be listed under Other Calendars.
Tap Save.
Please allow up to 20 seconds for the changes to take effect.