Fed Up

I took out a contract phone A Mandela Freedom Phone not knowing it's a Chinese brand , called many times for the returning the phone but nothing worked out, after a week the screen broke till to date I can't find a screen for the phone , so now I wanna settle their existing debt as it's affecting my score still I have to struggle after spending so much airtime on calling, I got told my account was handed over to another company for collection so I called the company they deny all of that .Good Day, kindly note as per our collections department your account has been handed to an EDC, You may contact GVDM regarding your account or further assistance on ***. I called the center again had to hold as I was transferred from one department to another till to date I can't settle this useless phone account. The service we get for this Chinese brand phone from Blue Label connect is really sad. I don't know now what to do because if they can't find my account and responding to their emails, where too from here please help as I'm losing my patience. Never Recommend anyone to buy this useless phone's which can't be fixed