Why is it always the "notifying" part that breaks with shitty software like this, and not the "money being taken forcefully" part, which always seems to work flawlessly? Doesn't that seem a little suspicious?

If they were uniformly bad at writing software, the critical money handling part should fail at roughly the same rate. If they can get that part to work reliably, failure of other parts of the system seem particularly inexcusable.