Last updated on December 16th, 2019 at 04:26 amHow to make a Complaint to Mercedes-Benz Mercedes-Benz operates an easy to follow complaints procedure. The first step is to call the complaints line on 1-800-FOR-MERCEDES (1-800-367-6372). If yours is not, then the subsequent steps to take are clearly shown on the website. Mercedes-Benz complaint contacts like Phone,