urgent pop ups

Perhaps someone (or something), or even perhaps yourself, have added an additional Calendar to your device - and this unexpected Calendar is exposing unwanted calendar events and sending you unexpected reminders. 

Let’s check for anything that’s out of place...

Settings > Calendar > Accounts

Look for an account that shouldn’t be in the list of accounts - as this will likely include the Calendar that contains all the unwanted events. When you find the suspect account, tap - then select Delete Account. This should resolve the problem in its entirety.

I hope you find this helpful in finding the source - and in resolving the issue if an unexpected Calendar is found

You’re very welcome. I’m pleased that the problem is now resolved.

Subscribing to a calendar is remarkably easy - and tricking the end-user into clicking a malicious link is increasing employed Threat Actors (the “bag guys”) to install the calendar - from which events can be remotely populated, with reminders, that will further attempt to manipulate the unwary into doing something unwise - or give away sensitive information.

The iOS/iPadOS ecosystem is very resistant to malware - but this mechanism is one of the few exploits that can readily bypass the strong protections of the OS; that said, it still requires the end-user to perform an action to get into your system.