The US Post Office does not have records of addresses from other countries.  When they ship internationally, I believe they transfer the mail to the local country's mail service; for example shipments to Australia are transferred to Australia Post for final delivery.  So there's no way for USPS to know if the address outside the country is correct.

Right now for you to get the package back, the USPS has to get in touch with the Dubai postal service and get it returned to USPS.  Sounds like a headache; I'd agree that you need to go to your local post office for advice.

This is correct.  Good luck to you.

Applications listed are 390 and 427.  Hoping someone has an extra they can spare.  Or a source for a repop would work too.