BAD, SHOCKING SERVICE AND ROUTE CONSULTANT

i HAVE BEEN WITH MTN FOR MANY YEARS BUT THEIR SERVICE NEVER IMPROVES INSTEAD IS EVEN GETTING WORSE DAILY, SINCE I TOOK MY PHONE TO MTN FOR A REPAIR LAST 20/12 TILL TODAY I DON'T HAVE MY PHONE, EVERY TIME I GO TO BOULDERS STORE BRANCH THEY TELL ME THEY DON'T HAVE THE PHONE BACK, TALKING ABOUT THE PHONE ONLY USED FOR 3 MONTHS THEN WAS A PROBLEM. I DO HAVE A SERVICE PROBLEM WITH MY OTHER PHONE WHICH I CALLED THEIR SERVICE 136 SO MANY TIMES AND KEEP ON TELLING ME TO DO SO MANY THINGS WHICH ARE NOT WORKING AND RESOLVING MY PROBLEM