Bad attitute and Non business ethics

I took a contract on the 15th of January 2016 for SONY M5 and non of the staff members informed me that the device has problems and other customers are already complaining about it. Sony has recalled the devices and when I took the phone back on the 22nd of January I was told the 7 days has elapsed and I cannot get another device instead they will send my phone to be accessed first before they let me have another phone. Other MTN branches let the customers returned their Sony M5 devices and they were given alternative devices on the same day. I am now without a phone for 4 days and they told me they will contact me but I am still waiting for their call.<br> <br> The service is so bad and the attitude is worse. All I want is to cancel the contract which I was told I cannot...WHAT THE HELL IS GOING ON WITH MTN MALL OF THE SOUTH???