My Reminders app is showing 6 reminders, but as far as I know, I have none. I've checked the completed file, checked in iCal on the Mac. Any ideas how to delete these reminders?
I've had this issue before. Turn off all reminders and turn them back on to reset the reminder data.
When you open the Reminders app, make sure there isn't anything set in both Reminders and Tasks.
You may have created a Task using Siri, or another app by accident. And as a result of the way the app is setup on the iPhone, it doesn't default to showing you both Reminders and Tasks at the same time.
On the iPhone try the following:
On the Mac try the following: