I went to USPS.com and tried buying shipping labels, but since they didn't print I clicked the "Do no charge my account, it did not print". Either way, I went to my bank account online and it says they are charging every single one. $70.00 in total. It's still pending, but I can't use that money.

What do I do? Do I call my bank or USPS?

You can do nothing as long as they are just pending. Anytime this has happened to me the pending transaction never actually goes through.