Payment reminders; edit body text

I've been trying to set up Payment Reminders, and keep getting text I can't find... and can't edit if I can't find it.

So far, I've set up Reminder Schedules, but I've got one that I still can't narrow down: Reminders are set to combine overdue invoices into a single email, as multiple emails seems inefficient and annoying. But when someone has invoices that fit into more than one "reminder" schedule, I get body text I can't locate anywhere in QB. It was clearly set up at some point by someone, but includes outdated information (contact name, banking info) so needs to be updated.

For clarity: The sample customer has two open invoice. One is 32 days out, so gets a fairly strongly-worded Reminder about sending payment. The second invoice is 28 days out, so gets a mildly-worded Reminder. The filter point is at 30 days. If I remove the tag to combine invoices into a single email, each invoice gets the appropriate body text. But if the marker is set to combine the invoices, I get a body text that's downright milquetoast (with, as I said, obsolete contact details), that I can't locate anywhere in the Payment Reminders system.

If the customer's account is flagged for both invoice and statement reminders, I get yet another mild, generic body text. This tells me there is still some place in QB that text is stored for payment reminders, that I haven't found yet.

Can anyone here help me find where else such default text is stored?