Tracking not updating and order was canceled?

Level 1
I sold an item to ship and for some reason the items tracking number still only says the label was created but nothing about usps receiving it. I eventually got a message that the I successfully cancelled the order?? Because the app thinks I never sent it?? So basically this persons getting a free item?? Any help with this would be apprrciated because I do not know what’s going on. Thanks.
Level 1

This happened to me today. Any suggestions?  I’m fearful OfferUp is providing a tool to help people steal money by cancelling orders mid shipment. Because of the polar vortex usps didn’t scan packages. Now my order is cancelled and I’ve already shipped. Any help please. Support won’t answer. Offer up customer service doesn’t service.