If you noticed an external damage to the box, you need to open and check its contents in the presence of post office employees and also need to check the declaration. In case if any of the items in the parcel are lost or damaged, you have to put together the acts, and take photos of all the packaging and enclosures. Also, you can refuse to accept the parcel.
We advise you to carefully inspect the outer packaging from all sides - the cuts and cracks on the boxes may not be noticeable at first sight.