In most cases, there is no invoice. Unpacking inspection means that when the courier company delivers the goods, the consignee can open it in person, but it must be marked on the courier list: Final unpacking inspection. This is also useful in the future, because if there is something wrong with the goods, someone can prove it. Now many courier companies don't let you go, only let you sign for it. Be sure to write these words and sign them.
You can discuss the invoice with the store.