Their sales practices are intentionally misleading and their warranty is a lie. I brought a Fitbit versa 3 from CEX as it was recommended by their sales assistant for swimming.
When I attempted to return the faulty item they sold me for repair I was informed that because I'd worn it in water I had voided the warranty.
They should have told me this when it was purchased but instead they told me I could swim in it. Their customer service team are doing their best to dismiss my complaints too and I feel the only way forward is to refer my complaint to trading standards.