Mercedes Benz lack of interest in customer correspondence

I took my car for the 100 000km service 12 May 2022 at Mercedes Benz Shelly Beach and was advised that the car milage is over with +- ****m and that a motivation will have to be done to head office to still service my car under the 100 000km service plan, which was declined by head office according to Shelly Beach branch, please bear in mind that I had to drive +- 200km to the nearest dealership which is in Shelly Beach.

I sent 3 e-mails to Mercedes Benz head office since 12 May last one being 02 June 2022, I still to date have not had a reply. I did the service cash but still believe that it should have been covered on the 100 000km service plan