Inzone H9 Headphones - defective!!

[zwilling]

After only 6 months, the leather section of my headset has come unglued, revealing the foam underneath in more than one area. I submitted a complaint and got a reply from customersupport.en@eu.sony.com stating that this isn’t covered under warranty. This seems like madness to me, as the product has clearly been poorly manufactured, and the headset defective. I would understand if it had happened after a couple of years of heavy use, but I’ve literally had them less than 6 months. Not what I’d expect from a headset that costs over £200!! Is there any way I can escalate this?? Looking online it seems like this is a common complaint for this product, and people have had mixed responses from Sony with some getting their repair free of charge.