In April i enquire about a device and the consultant assisting me the device have all the features i was looking for only to find out it was not the case

In April i enquire about a device and the consultant assisting me the device have all the features i was looking for only to find out it was not the case. When requested to returne the device i was send back and forth from one department to another without the matter being resolved. So i am still struggling for someone to help me getting this resolve because i am now being charge for a device i do not have. I have send Mtn so many correspondence and phoned them but without any luck. I am frustrated and do not know what to do.