I'M PAYING FOR A PHONE THAT IS NOT IN MY POSESSION

I bought a iPhone 6sPlus from Vodacom Repairs Century City on a 24 month contract. Hardly 4 days the software of the phone crashed. I returned the phone on the 2nd of Nov 2015 and was told that it would be sent to the Head Office and would be back within 5-7 days.Up until today I still do not have the iPhone yet my account has been debitted twice totalling to almost than R1 200 and yet I do not have the phone.I went to the store on the 14th Nov and was told that they didn't understand why the Head Office didn't authorise so that I could get a new phone but was assured by the Supervisor Yolandi Myburg that it would be followed up this week.I called again on Tuesday 17Nov and was made to hold for more than 10minutes as \the Manager was busy".He never called back as promised and I STILL DO NOT HAVE A PHONE WHICH I PAID FOR.I just called again and was told the same explanation by the Manager Umar Abrahams that it would be followed up.At this point I want to CANCEL MY CONTRACT WITH VODACOM WHO HAS BREACHED THE 24MONTH CONTRACT BETWEEN MYSELF AND THEM. WHY MUST I PAY FOR A PHONE THAT I DO NOT HAVE? """