Am I being hacked?
I am getting notices that my Icloud was hacked, is that possible?
If running iOS 13 or earlier versions, check: Settings - Passwords & Accounts - Accounts - Any rogue entries here? If so, delete the rogue account.
If running iOS 14 or higher, check: Settings - Calendar - Accounts - Any rogue entries here? If so, delete the rogue account.
The Apple support article is below.