appalling service from Renault SA and Renault dealership

enquired with Renault Pinetown on the service cost for my 2020 Renault Duster. was told i had to replace the cambelt 4 years or 90000kms although vehicle is only doing 39000kms. enquired with Renault SA and was told to change cambelt 3 years or 90000kms. asked for documented evidence of schedule for serviceable replacement parts. told it doesnt exist. only verbal communication which clear indicates inconsistencies and subject to ones lack of knowledge. extremely appalling service from Renault SA. owned both 1st & 2nd generation Dusters and uncertain about remaining with the brand.