They sold you a lemon and now they are ghosting you.

A retailer rejected your warranty claim and now they are ignoring you. This drafts a sharp escalation letter to head office that cites the Consumer Rights Act 2015, rejects their diagnosis, and makes clear you will pursue a Section 75 chargeback through your card issuer. Firm, factual, and built to get the response the front-line staff would not give.

Write a sharp escalation letter to the retailer's head office after my warranty claim for [item] was rejected on the grounds of [their stated reason]. I bought it [number] months ago and paid partly or fully by credit card. Cite the Consumer Rights Act 2015 (goods must be of satisfactory quality and fit for purpose), reject their diagnosis, and make clear I will pursue a Section 75 chargeback with my card issuer and a small claims court filing if they do not respond within 14 days. Do not apologise.