USPS picked up Priority Mail but it's not showing in the system

[mif093]

Hello,

I mailed two different blu-rays, to two different buyers via USPS Priority MAil flat rate envelope on Monday November 23rd. My doorman gave it to the USPS carrier. There were two Flat Rate envelopes in a plastic shopping bag. One envelope shows it arrived at a USPS facility Monday night (there is no information after Monday Night). The other Priority Mail Flat Rate envelope e that was in the bag reads label created and USPS awaiting item. Both envelopes were picked up Monday November 23rd. They were in the same bag. As of November 25th at midnight one envelope that arrived at a USPS facility has no information beyond Monday night and the other is showing in the system never received. I did open a package search case with USPS for the one reading awaiting item. This has never happened to me before. What should I do? At what point would I have to refund the buyer? I know when I printed the label it read 3 day delivery which has not happened yet.

Any advice would be appreciated.