MERCEDES WARRANTY IS WORTH NOTHING

My car went in for a service (it has about 80 000km) on. The transmission warning came on and mercedes have come back to me to say a component failed which costs R12 103.96 along with labour of R 2770.00 to fit it. I feel it should NOT have FAILED and should be entirely covered by Mercedes. This is a MAJOR FAILURE. They maintain its a maintenace issue as the car is older than 2 years from Manufacture. WHAT A COPOUT. They dont stand by their vehicles. Our other vehicles. HUNDAI and AMAROK and TOYOTA , NEVER had as many issues and in fact HUNDAI covered their gearbox under warrantee OUT OF MAINTENANCE PLan. MY Mercedes aircon did not work when I bought it inspite of the 72 point check. Two months later the entire locking system had to be replaced as it did not lock inspite of the diagnostics stating otherwise. The electric windows give trouble. The B Class Mercedes is exactly that a SUBSTANDARD CAR at a premium Price.