Rear camera was standard equipment from the 2016 model year forward. Maybe 2015...but definitely 2016. Didn’t have your problem but got the same BS excuses from my dealer for my issue. Go to mbvans.com and download manuals and brochures that show camera as “Standard”. Do you have the original invoice? It will show rear view camera. VIN will confirm also. Smile and push to have it checked. Don’t be pissy. If all else fails, call mbvans customer service in Atlanta. Although when I called they played just as dumb as the dealer. Took me a month of pestering before my dealer finally took my van in to scan the software...begrudgingly. Problem was found and fixed. Don’t let them run roughshod over you.