Won't claim repsonsibility for blown tyre

Sold my wife a set of cheap knockoff tire. One failed on a highway (1000 km later) and now they won't claim responsibility for the blowout, nor refund me for the perfectly good other tyre which I don't trust.<br> <br> They sent it off to manufacturer and they claimed impact damage (there was no impact damage!). There is a 5cm rip on the INSIDE wall of the tyre. <br> <br> I've had no responses from them, I've constantly had to be the one who phones and follow up. I will not recommend anyone using them.