faulty phone revieved and not willing to help

I RECENTLY TOOK OUT 3 MOBILE CONTRACTS FROM TELKOM MOBILE THROUGH THEIR CALL CENTRE.THE PHONES WERE DELIVERED ON A FRIDAY AND I ALREADY LEFT THE OFFICE SO I ONLY RECIEVED THE PHONES ON MONDAY. THE 2 SAMSUNG S6 HAS NO PROBLEMS BUT THE SONY EXPERIA Z5 GETS SERIOUSLY HOT AFTER ONLY 10MIN OF USE AND GETS HOTTER EVERY SECOND AS I CANT HOLD IT ANYMORE IN MY HAND. I CALLED TELKOM THAT FRIDAY MORNING TO EXPLAIN TO THEM THE PROBLEM WITH THE PHONE AND THAT ITS STILL IN THE 7DAYS RETURN PERIOD AND I WANT TO RETURN OR EXCHANGE THE PHONE FOR SOMETHING ELSE ON THE SAME CONTRACT AS ITS SEEMS AFTER SOME RESEARCH SONY Z5 PHONES HAS A OVERHEATING PROBLEM AND TELKOM SHOULD HAVE MENTION THAT BUT THEY DIDNT ANYHOW AFTER ABOUT 45 MIN WITH TELKOM ON THE PHONE AND SPEAKING TO 9 DIFERENT PEOPLE AND 4 DIFERENT DEPARTMENTS NO ONE SEEMS TO KNOW HOW TO HELP ME SO AFTER SPEAKING TO THE 10TH PERSON A COURIER WILL PICK THE PHONE UP FOR INSPECTION...WELL 3DAYS LATER STILL WAITING FOR COURIER I CALLED TELKOM AGAIN AND NOW THEY WANT ME TO TAKE THE PHONE TO A TELKOM SHOP TO BE BOOKED IN FOR REPAIRS!!REALLY ITS A NEW PHONE AND WHY SHOULD I SIT WITHOUT A PHONE AND BE TREATED LIKE THIS WHEN IT CAME FUALTY FROM TELKOM???