Is it new ? If so I’d send the pictures to them as a complaint and see what they say. It does look like a scratch but could just be the pictures maybe.
Is that a piece of wood on top of the solid base or the base itself ?
Looks like particle board; that stuff is not really suitable for stands but since it is cheap stores still use it. If new you can try to return it and claim it was defective; either way you really want a real wood or metal stand if your aquarium is 29 gallons or larger. If smaller you can get away with particle board but if the stuff gets wet it will fall apart (if the water gets under the paint or if the back is unpainted and it becomes wet).