We attach great importance to the highest quality of our in-house substrates. If you should have any complaint about a GMG medium, please contact one of our sales channel partners. They will handle the complaint for you and arrange a replacement. In addition to our own media, you can also purchase substrates from our official media partner JetComp via us. If you have any questions or feedback about these media, please contact JetComp directly. This is the fastest way to get competent feedback on your individual request.