Poor service no body would take responsebility

My name is Lesego on the 4th Dec. 2016 I phoned MTN to apply for IPHONE6s PLUS. I was assisted by Vusi Dube and after all the questions he asked he immediately confirmed that my application was successful and I should expect my phone within 5 working days. Okay I then waited and had to call them to enquire about my phone because after 5 days I still didn't receive it. When it was delivered on the 11th of Dec. to my surprise it was a wrong phone IPHONE6s instead of getting IPHONE6s Plus. I then phoned again and I was told to go to the nearest MTN dealer went to the nearest they refused to take it and told me to go to Wonderboom Junction. I then went to wonderboom and Freddy assisted me and took it back told me that MTN Online will contact me. I was given this Ref. no. ***7. I have contacted MTN the whole of last week and still could not get answers as to what going to happen all I get is they will send their manager an email. I don't have a phone and this is not my fault at least send back the phone that I was given then. Since no one is able to give me answers. This is unacceptable