My packet doesnt seem to go through?

Okay so I recently sold my old phone on vinted. I got the official shipping lable, printed it and went to drop it off at a local store.
They never scanned it, and I didn’t get a receipt that it was shipped, so that‘s that- But it‘s on it‘s way? As in if I ask the people at the store they say it was collected, but on vinted itself nothing updates? And now the person who bought it doesn’t respond to my messages.. I really don’t know what to do, does anyone know what I could do?