The second one was notification that they would be charging our "prepaid accounts" the next day (Saturday Sept 17) for the next month's services. It was very much more of an invoice (breaking down what they would charge us for) than the first email.
If anyone did have a credit card attached to their account, they're looking at it from the fraud angle. Everyone else is wondering if they're going to try to force some kind of debt collection because we are not going to pay, that's likely where the knives-out reactions are coming from.
Doing an automatic in-place "upgrade" from a free tier to a paid account tier to years-old accounts (and without customer consent!) is a scummy move. Even if not intended to be malicious, it's an idiotic thing to do, especially business-wise. They just flushed away any good will leftover from their acquisition of the FogBugz name.
The cherry on top is that any attempt to log into the account to cancel it, or to contact customer services (which requires creating a customer service account) errors out, so any of the legitimate ways one might think of using to address the situation are blocked.