iPhone
I keep receiving an alert from my calendar saying my phone lock soon because of vpn and spam detection
iPhone 12 mini, iOS 14
Do not interact with the messages, or click on any of the bogus calendar entries.
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, check: Settings - Calendar - Accounts - Any rogue entries here? If so, delete the rogue account.
The Apple support article is below.