Cooper tyres are the worst

Bought 4 brand new bakkie tyres in September 2019. Received an sms from Cooper tyres to rotate my tyres. Went to the dealer where I bought for the rotation to find out there's a bubble on my right rear Tyre. Hardly drove my bakkie due to the Pandemic and working from home. Tyre thread was between 70 - 80%. The dealer decides to do a claim just for them to get a report back from Cooper tyres to say there's nothing wrong with the Tyre. The bubble was due to climbing a kurb or a bottle. What nonsense reasons are those. I think this is one of the worst Tyre brands in the industry. I will not recommend anybody to buy this brand. I don't even think I did 10 000 kms on these tyres. My bakkie is not even 4x4. Worst Tyre brand