Anytime! Good idea. Idk, I’m thinking USPS is super slow since it’s Christmas time. If the tracking numbers don’t update by tomorrow or Monday afternoon, I would contact Amazon and let them know that you shipped the books before the due date (but the tracking number isn’t updating) and if they can hold the late fee charges (not sure when they start charging, but hopefully they take the holiday season frenzy into consideration). Good luck!
Regarding the apex_media horror stories: my older sis eased my mind by reminding me that with every company/service, there are always people who complain. Sure, some are probably honest, but some of them probably didn’t ship the books out before the due date and are mad about the late fee charges.