If you receive unwanted calendar invitations or event notifications, you may have subscribed to a spam calendar by accident. To remove the events, delete the calendar subscription.
Open the Calendars app.
Tap the unwanted Calendar event.
Tap Unsubscribe from this Calendar at the bottom of the screen.
To confirm, tap Unsubscribe.
Open the Calendar app.
At the bottom of the screen, tap Calendars.
Look for a calendar you don’t recognise. Tap the next to that calendar, then scroll down and tap Delete Calendar.
If this doesn’t fix the issue, delete the calendar subscription in Settings:
Open the Settings app.
Tap Calendar > Accounts. Or if you use iOS 13, tap Passwords & Accounts > Accounts instead.
Tap Subscribed Calendars.
Look for a calendar you don’t recognise. Tap it, then tap Delete Account.