When Customer Gives you an Order Number, Can you see all Items associated with order? Price per item?

I had an amazon seller wanting my order number to manually refund me. They did, but they ended up refunding me more than the amount of the item and seemed to have included the other items unrelated that were in that same order. (yes I accounted for taxes and shipping)

So when we provide an order number to a seller what can they see ? do they just see a total price paid that will include other random items ? or can they see what is specifically their item that they sell?

Is there any way they can tie it up to a specific order from their seller account and verify the amount? Seems odd they over refunded me or something I don’t know