Microwave sent for repairs comes back works for less than a week,now not working again.

I bought a microwave from Braamfoentein Fair Price in January 9 months down the line itsvnot gearing up food.When I take it back im told I have to leave it for 35working days.Well what choice did I have.After those 35 days I receive a call to go and collect it did so.Worked well for less than a week now it’s not working again.When I call in the branch the salesman sounds clueless because i told him I can’t take it in for another 35working days and for what it’s worth I know everything about my CPA.I need this resolved asap I can’t wait another 35 days this time never!!!