2001 Mitsubishi Diamante

MY HEATER CORE WENT ON MY AUTOMOBILE. THE CAR IS A 2001 MITSUBISHI DIAMANTE WHICH HAS 50,000 MILES ON IT. THE PROBLEM STARTED WHEN THE CAR HAD 45,000 MILES ON IT, BUT I DIDN'T KNOW IT WAS THE HEATER CORE UNTIL LATER ON. THE DEALER HAD THE CAR FOR 2-L/2 DAYS FOR A JOB THAT WAS 6.9 HOURS. I WAS TOLD THAT THE BOX THAT THE CORE WAS IN WAS EITHER BROKEN OR COULDN'T BE SHUT, BUT THEN THEY WERE ABLE TO CLOSE IT, FIX IT I HOPE. I WAS TOLD BY ANOTHER MECHANIC THAT IT COULD HAVE BEEN THE O-RING AND THAT THEY HAD A CAR THE SAME YEAR WITH THE SAME PROBLEM, POSSIBLE RECALL. THE DEALER DID A SHABBY JOB IN REPLACING MY DASH BOARD, I HAVE 3 SCREWS THAT I FOUND ON THE FLOOR, MY GLOVE COMPARTMENT HAS A SCREW MISSING, NONE OF WHICH I HAVE IN MY POSSESSION FITS THE MISSING SCREW HOLE. WHEN I PICKED UP THE CAR, THE STEERING COLUMN CAME APART IN MY HANDS AND SO THEY TOOK IT BACK IN TO FIX. DO THEY NOT CHECK THINGS AFTER THEY COMPLETE A JOB, LIKE ARE ALL THE SCREWS BACK IN PLACE. I WILL NEVER BUY ANOTHER MITSUBISHI AND NEVER ADVISE ANYONE TO BUY ONE EITHER. I WAS TOLD THAT A HEATER CORE SHOULDN'T BREAK AT ONLY 50,000 MILES AND THE CAR IS ONLY 3 YEARS OLD.