Rude Renault sales manager

I bought a pre owned car from Renault Imperial Fountain Branch and the car tyres are worn out, when I went and notified the Sales Manager about the tyres as I went to tiger wheels and tyres to be checked, the sales manager told me that he cannot replace the tyres as they are road worthy, yet I have the tyres inspected by the specialist and he even confirmed by calling the person who inspected the car, is this the service we should be getting from a dealership were I pay a big installment every month, funny enough when I traded back my car my tyres were ticked out as worn out yet they failing to replace the one I just bought, this service is so pathetic and unacceptable because when I go there he looks at me like I am pain in a butt, this is so not on