Terrible Service from MTN

I booked my device in for a repair at the Mtn Liberty Midlands Mall store with regards to my wifi not activating. At the repair center I was quoted for an amount of R1700. When i called to check what was quoted i was told for a cracked screen which my device did not have when being booked in at the store. I asked for my device to be sent back as i was not prepared to pay for physical damage on my device which was not on it. Upon arrival of my device I received a totally different device. Now the MTN store and repair center do not know where my device is, they say that the matter of locating the device is under investigation but at the end of the month i am still liable to pay for this device which i did not misplace. Regards Kiveshan Padayachee ********** 685