2006 MERCEDES BENZ ML63 Engine Problems

WHILE DRIVING, THE CHECK ENGINE LIGHT CAME ON AND THE VEHICLE STARTED MAKING A ROCKING NOTHING, DID NOT KNOW WHAT WAS GOING ON AND SO I STOPPED VEHICLE ON THE SHOULDER. I CHECKED THE GAS TANK TO SEE IF THERE WAS A PROBLEM WITH THE COVER. WENT BACK IN THE VEHICLE AND TRIED TO RESTART, VEHICLE WOULD NOT START. I CALLED THE TOW TRUCK AND HAD THE VEHICLE TOWED TO THE DEALER. SPENT $576. FOR DIAGNOSIS AND WAS INITIALLY TOLD THAT THE CYLINDER HEAD WAS BENT AND THE INTAKE MANIFOLD HAD A PROBLEM. I WAS TOLD ME THAT I MAY NEED A NEW ENGINE. I WAS TOLD THAT IT WILL COST $5600 TO FIX THE PROBLEM AFTER I COMPLAINED TO THE CORPORATE OFFICE THEN I WAS TOLD THAT IT WOULD BE $4300. II STILL DO NOT HAVE MY CAR UP TO NOW BECAUSE I WAS MADE AWARE THAT CAR NEEDS...