Cell C won't help me cancel a contract

I did an online application over the phone helped by a lady by the name of Tshepo Mahlangu. She have me the email address to send all the required documents and in the email I told her the specific phone colour I want. The phone was delivered and the box showed the exact colour I said I don't want but I thought its not always the case and I would find the right colour inside but unfortunately No. The problem is that it's a gift for a child and he was specific with the colour. Now I have been contacting Cell C all morning and sending emails to this Tshepo lady with no response. Every department transfer me to the wrong one and eventually hang up before I even get to the right department. I was willing to take a different phone with Cell C but at this stage I see them for what they are and I just want them to take their phone back and cut ties. I don't deserve this this kind of service that I pay for. They are doing this to ensure that 7 days passes and then deny to take the device back.