no phone for over 5 days

I had just upgraded my contract on The 13th of june to a samsung s6. After the 5th day of having the phone i had taken it back to the store as the battery was draining way to fast. They said they would assest the phone and it would be couriered to jhb. They also said it would be 3-5 working days. Today is day 8. Something about back log in jhb. I will be currently sitting without a phone from Friday which i use for work as well! I need a phone and this is absolutly ridiculous now! I want to cancel my whole contract as i have only had use of the phone for 6days total. So i do not want to pay for something i havent even used. Second time this year already having problems with vodacom.