Mercedes-Benz Sandown SHOCKING all round

I bought the very expensive GLE 450 Coupe about 4 years ago and have done about 56 000 km. The suspension on this car gave in three times in the last year. I took the car in to Mercedes-Benz Sandown 16 days ago (they've done all services on this car). I have lost confidence in safely driving this car and in Mercedes-Benz service and ability to fix issues. I have communicated with the service manager, Marco, the customer officer Koos and the dealer principle Alex. No one has come back to me on options requested 16 days ago! This is not only an awful reflection on Mercedes-Benz as a whole but also completely unacceptable.