Rust stains on the blackboard

A piece of the board surface is chipped after only a short time to about 3 cm, including rust and it is formed slight bumps. An inscription of the panel is not really possible, because due to the slight increases no uniform typeface is guaranteed. I use quality pens of Staedtler, but this can be difficult to remove from the board. It seems to me to have been very save in the material quality of the surface. This is contrary to the article description does not know and scratch-resistant, but rather dull and slightly gray and not very well protected against the rough bottom of the magnets. Had I not already disposed of the packaging, I would send it back.