BAD CUSTOMER SERVICE AND NO DELIVERY

I refer to an MTN CONTRACT PHONE that was offered to me by MOBILESTORE on the 10/11/2017. The phone was delivered to my workplace by MTN's Courier Company (DSV) on the 01/12/2017 but the colour of the handset was wrong, i then went to MTN store in Parkstation (JHB) but i was referred to the MTN Service Centre at Westgate Mall. I went to MTN Westgate Mall on the 03/12/2017 with the handset and the Simcard (sealed) and i was assisted by a guy named Sphamandla Mbatha who told me that it was possible for me change the colour of the handset but he will have to send it back to the Warehouse in MIDRAND. He gave me a document confirming that i gave back the handset and his contact details ( ********** 642) in order for me to make a follow up in a week's time. I contacted him on the 13th and the 14th/12/2017 but he did not answer his phone so i went to the store again on the 15/12/2017 and he contacted the contact centre ( ********** 256) and we were assisted by a lady named JASLIN BENNY who told us that Sphamandla was not supposed to take back the phone from me because MTN does not allow any colour changes, he told the lady that they do it all the time because a lot of their client goes to their store for exchanges. We were not getting any joy at all and he told me that he will log an enquiry to the warehouse to find out the status of the handset and that he will again get back to me within 48hours. He did not answer his phone again on the 18-19/12/2017 and i decided to go back to the store again. He then told me that the warehouse did not get back to him, i was so angry and i decided to escalate the matter to his senior because i received a billing statement on the 14/12/2017 for a handset that i did not own and my simcards were sealed but on their system they were activated. I was then assisted by her supervisor by the name (LERATO) who then contacted her friend that works at MTN but I'm not sure of the branch name she/he works for who then told her (LERATO) that the warehouse is closed and they no longer have stock of the handset (HUAWEI P8 LITE (2017)) that i returned to them. She then told me that they do have stock in the shop and the colour that i wanted (BLACK or GOLD) but she is not allowed to exchange it for me hence my handset was taken to the warehouse. I told her that it is not my fault that the warehouse was closed and that they did not have stock because i handed my handset to them the beginning of the month. She then promised to get back to me after 12:00 the following day because she had a meeting from 10:00 to 12:00 but she had to contact her friend first to find out how to get closure regarding the matter. I am still waiting for her phone call (a week later) with no courtesy call or nothing for that matter. I contacted a whole lot of MTN numbers to get assistance regarding the matter but i am getting no joy instead i get transferred from 1 consultant to the other. I really don't understand why must i suffer for their lack of professionalism and incompetency and is it really fair for me to wait for a handset for a month only for a colour change? Please help.