Summary:
See support email. There's nothing tricky here, we were just missing a check. The different parts of this got built at different times so I think this was simply overlooked.
Also add a redundant check just to future-proof this and be on the safe side.
Test Plan: Used `bin/phortune invoice` to charge a pact subscription. After deleting the card, the charge failed with an appropriate error.
Reviewers: amckinley
Differential Revision: https://secure.phabricator.com/D19020
2bb4fc9ece