I bought a device through an Amazon seller. It developed a fault after 10 months, within the warrenty period. The seller told me to return it, but then after

I bought a device through an Amazon seller. It developed a fault after 10 months, within the warrenty period. The seller told me to return it, but then after I sent it they would not answer emails. After three months with no contact I started complaining. In the end Amazon told me they could do nothing and recommended I perform a chargeback!