Did you try a different postal clerk? Some are better at their jobs than others. Or can you write to the sender? If worse comes to worse, ask for the Post Master.
As stated, it’s been very busy. You can’t just go from one to another. Actually, she asked another worker (manager?) about it when I was there.
If it’s not busy I would ask more of them.
Also, this PO ain’t so great with attitudes, but it’s a distribution center. There is another PO down the street which usually has very helpful people. I like it better but alas. I might have to ask them.