FAULTY PHONE AND DISGUSTING SERVICE

I TOOK OUT A NEW CONTRACT WITH MTN AS I WAS A CELLC CUSTOMER AND DECIDED TO CHANGE OVER DUE TO POOR RECEPTION.I TOOK A SAMSUNG NOTE 4,THE SERVICE FROM CONSULTANT WAS FAIR,HOWEVER THE NEXT DAY I STARTED EXPERIENCING SOFTWARE PROBLEMS WITH THE PHONE.IT WOULD SWITCH OFF AND RESTART ON ITS OWN AND SOME OF THE APPLICATIONS WOULD NOT OPEN OR CLOSE.I TOOK IT BACK TO THE STORE AND EXPLAINED THE PROBLEM BUT BEING SOFTWARE RELATED THE PROBLEM WAS INTERMITTENT AND WORKED FINE.HE SAID TAKE IT BACK HOME AND USE IT,IF STILL DOING SAME HE WOULD SWOP IT OUT FOR A NEW PHONE THE NEXT DAY.CAME HOME AND STILL STARTED FREEZING UP.I TOOK IT BACK THE NEXT DAY AND HE REFUSED TO SWOP IT OUT,SAID HE NEEDS TO SEND IT FOR REPAIRS AND THERE WAS NOT EVEN A CALL MADE OR RECEIVED ON THE PHONE.HE STARTED INSULTING ME IN FRONT OF OTHER CUSTOMERS.AS A FEMALE I WAS VERY HUMILIATED AND HURT.HE SAID IF HE NEW I WAS GOING TO BE SUCH A PROBLEM CUSTOMER HE WOULD NEVER HAVE DONE THE CONTRACT N TOOK IT UPON HIMSELF TO CANCEL IT.I WAS SO DISGUSTED BY HIS BEHAVIOR PLUS MY FAULTY PHONE I AGREED.HE SAID WILL EMAIL ME AS SOON AS CANCELLED BUT NOTHING YET TO DATE. SUCH HORRID PEOPLE ARE DESTROYING MTNS NAME.PLEASE ASSIST