Priority Mail Express has a guaranteed delivery date that is based on the origin of shipment, time shipped, and the destination.
But what happens if your shipment doesn't arrive in this guaranteed time-frame? You should request a refund! Learn more here.
How to: Get a refund for a late Priority Mail Express delivery
What is Priority Mail Express?
Can I send a return shipment via USPS Priority Mail Express?
Can I get a refund on postage for returned items?
What to do if a package is returned due to not enough postage?