BAD DISGUSTING SERVICE

I WAS AT MTN BRITS MALL ABOUT 3 WEEKS BACK, I DID AN UPGRADE ON AN IPHONE 6 AND THE THE PHONE WAS AUDIO FAULTY I COULD NOT HEAR THE OTHER PERSON TALKING I THEN TOOK IT BACK TO MTN BRITS MALL OF WHICH I PROMISED TO BE CALLED WITHIN 7DAYS OF BOOKING MY IN TILL TODAY I HAVE NOT HEARD ANY RESPONSE FROM I HAVE TO GO THERE EVERY WEEK TO FIND OUT WHATS GOING ON.ITS BEEN 3 WEEKS NOW I AM PHONE-LESS AND I HAVE BEEN TOLD THERE'S IS NOT STOCK. THIS IS REALLY DISGUSTING THAT A NEW PHONE CAN TAKE UP TO A MONTH TO BE REPLACED YET I HAVE TO CALL THE STORE EVERYDAY TO FIND OUT THE OUTCOME ON MY DEVICE. IF I DONT GET THE NEW PHONE BY FRIDAY I WILL CANCEL MY CONTRACT AND GO TO OTHER SERVICE PROVIDER CLEARLY MTN DOESN'T WANT MY BUSINESS ANYMORE.THE STAFF ARE AT BRITS ARE NOT HELPFUL AT ALL INCLUDING THEIR MANAGER I AM ACTUALLY DONT WANT TO BUSINESS WITH THAT BRANCH!!! I WANT MY NEW HANDSET BY FRIDAY OR CONSIDER THAT CONTRACT CANCELLED.