What should we do when App Review just makes rules up?

I was just rejected for the following:

Guideline 2.1 - Performance
We found that while you have submitted in-app purchase products for your app, it does not show the expiration date in the app after a subscription purchase is made.

However searching section 2.1 I can't even find the letters 'exp' (looking for expires, expiry)

As far as I can tell - this requirement isn't anywhere in the rules. It looks like App Review (or a reviewer) are just making things up.

How should we handle this?