Why do my rear breaks make a grinding high rubbing sound? on 2008 Mazda Mazda5

When in reverse only the rear breaks make a hard grinding rubbing noise. The dealers says breaks ok. But still not acceptable. Mileage 85000 km. 4years same brakes

Asked by for the 2008 Mazda Mazda5
1 answer 1 comment
How many miles (km) since it was last checked? Hard for us to argue with a dealer that can look at the vehicle!
78000 also rubbing noise rubber on rubber almost like the brakes are sticking on