CONTRACT ACTIVE BUT NO DEVICE

I HAD A CONTRACT UPGRADE WITH MTN STORE IN HATFIELD PRETORIA ON THE 14TH OF AUGUST 2015 AT 9:30. WE FILLED IN ALL THE PAPER WORK AND THE CONSULTANT GAVE THE PHONE TO ME. I THEN GAVE IT BACK TO HER PHYSICALLY IN THE HAND TO PUT ON ALL THE ACCESSORIES THAT I WANTED TO BUY. I WENT OUT OF THE STORE LEAVING MY SISTER WITH THE CONSULTANT AS SHE WAS THE ONE THAT WAS SUPPOSED TO TAKE CARE OF THE PAYMENTS AS SHE IS THE CONTRACT HOLDER. BONGY MCUNU WHO IS THE CONSULTANT TOLD MY SISTER THAT THEY MUST PAY FIRST BEFORE SHE PUTS THE ACCESSORIES IN. IN DOING THIS SHE PUT THE PHONE DOWN ON HER TABLE AND LEFT IT UNATTENDED AND TOOK MY SISTER TO THE PAY POINT ON THEIR RETURN TO THE TABLE THE NEW SAMSUNG GALAXY S6 EDGE WAS NO LONGER ON THE TABLE. I WANT A NEW HANDSET OR THE CONTRACT WITH MTN MUST BE TERMINATED WITH I****IATE EFFECT.