"Disabling iCloud, App Store, and Apple ID accounts is actually an Apple Card policy for overdue accounts". This is very strange and worth complaining about. If the iCloud subscription is up-to-date, being less than 14 days late on a credit card payment shouldn't disable it.

Edit: wait, this seems to be contradicted by the blog post. I'm following up on Twitter.

Edit2: "It's policy, but not in the agreement." https://twitter.com/dcurtis/status/1366579647564181507

"But the trade-in kit never arrived."

Apple was supposed to send him a trade-in kit for the old MacBook Pro. Apple failed to do so. Then Apple added an unexpected charge to the card for the amount of the trade-in credit.

Locking someone out of their (unrelated) account is definitely not normal behavior for missing a payment, nor should it be.