Mazda CX 3 Rear seat belt and Car seat

I am driving a Mazda cx3 individual auto 2016 Individual auto that is now under warrantee and i am disappointed with the car.
My driver's seat belt is not working, and the leather seat is pealing it was changed when the car was still under warranty and the leather on the steering wheel is also pealing. I am disappointed with the car.
This was supposed to be an executive car as it was a top of the Range. I drove a BMW before and i drove it for 10 years without giving me problems.

I went to the dealership they told me that the belt will have to be ordered and they coded me for replacement and for the sale of the belt.

When i drive my car i have to make sure that people a sitting at the back seat.

But with Mazda it disappoints me every day. Their safety is a very serious issue for me.