2012 AUDI A5 CABRIOLET Engine Problems

MY CAR HAS HAD THE ADD OIL LIGHT ON MANY TIMES TO WHICH I HAVE TAKEN IT TO THE DEALER. FIRST TIME THEY TOLD ME IT WAS A WATER PUMP FAILURE. I REPLACED AND PAID FOR THE WATER PUMP. SECOND TIME A YEAR LATER I RETURNED TO HEAR THAT THE WATER PUMP FAILED AGAIN ONLY THIS TIME IT WAS THE CAM BEARING LADDER THAT FAILED WHICH IN TURN CAUSED THE WATER PUMP TO FAIL. BOTH TIMES I ASKED IF THE WATER PUMP IS REPLACED SHOULD I REPLACE THE TIMING BELT, I AM TOLD IT IS A TIMING CHAIN AND DOES NOT NEED TO BE REPLACED. THEN THE LIGHT COMES ON AGAIN I TAKE IT BACK TO THE DEALER TO BE CHECKED THEY SAY IT IS FINE. TWO MONTHS LATER THE LIGHT COMES BACK ON, WHILE DRIVING TO THE GAS STATION TO GET OIL I TURN ENGINE OFF ONLY TO HAVE...