FAILURE TO EXCHANGE THE DEVICE FOR ,I RETURNED THE DEVICE WITHIN 7 DAYS OF PURCHACE

pathetic customer service from MTN MALL OF AFRICA,I took a device via contract with the 3 days later I have noticed that the the camera has a problem ,seems like the camera lens has broken inside, they refused to exchange the device for me, it has been a week now without the device , I have only used the device for 3 days (Apple I phone XR) I know the policy that says if the customer returns the device before 7 days they have to exchange it and give me the new one but no not with MTN, been calling the store so many times no one is answering I still don't have a phone now, I wanted to cancel the contract with them to go somewhere else , they told me I have to pay R9840 and the device is only 6999, I no longer want the device or any contract with them I just want to cancel, all the staff don't have sense of emergency,