Cheated, don't buy from them

I bought 4 Michelin tyres from you guys, cost me over R22k... when I spoke to the sales adviser I said make sure you give me the best... not even 6 months later I have a tyre burst on the highway. I took the tyre back to the store over 3 weeks ago only to be told my claim is declined. This is really really frustrating for me as these tyres are very expensive, I never had issued with it. We've been on lockdown so I haven't even driven the car that much. I am seriously disappointed and would appreciate if someone senior can look into this matter for me. I even doubt that the consultant from Michelin escalated my matter. Please escalate this to senior management as soon as possible.