Notification from a 3rd Party on my Lockscreen

I am getting notifications on my lockscreen that I am near a particular location. On the left I see the icon of a ticketing service where I recently purchased a ticket (using my Mac) to that location. (Event title is displayed as the location.)

Easiest explanation is the service' app has access to my location, background refresh enabled, and permission to give notifications. Makes sense, but I have never downloaded that app.

Have provided a screenshot to Apple advisors. They are just as mystified as I am.

The service has my email address, which I use with iCloud, & knows I am scheduled to attend a future event. I can't see how they are able to create this notification.

I could turn off all notifications & location services, or sign out of iCloud, but that would be overkill.

Anyone experience the same, or similar? Any idea how to control this?