What Mercedes don't tell you when you buy a GLC

I have recently owned 2 Mercedes GLC vehicles. I recently became aware of unusual tire wear and contacted MBSA and looged a query , I was contacted about a week later and told that they would look into the matter and resolve within 48 hrs. More than a week has passed and no response clearly too hard to resolve, not sure what to say. When contacting the dealership I was advised that after speaking with the technical division at MBSA they are of the opinion that the life span of front tires are about 25,000km. This is crazy to say the least tire life on all other vehicles I have owned goes many more km's -why is this not told up front or documented surely this is a problem????