Poor client service

I had new tyres put onto my car in mid January and my car was shaking eventually they’re mart booked an appointment with your rep and he came to meet me today ,two of the tyres are faulty and I’ve never heard of a place then only replacing two .did I not buy 4 tyres all together? Why are only two being replaced! After having to go back and forth more then 4 times to have the wheels balanced .no sense of care and I have been a valued client for the longest time .when I asked the rep I’d like all 4 replaced as I bought 4 and 2/4 are faulty I was told no straight with no I’ll see what I can do I understand ur frustration everything.and he measured the tyres no thread was even used!