Extremely bad and poor service

I received a call selling me a Samsung A2 Core as a part of my upgrade that I had recently done. I told the consultant to call me later as I was in a shop and she told me that this offer was only available for that day only. I agreed and she did the sale. When the phone was delivered I did not meet the person who delivered it, whom I was told would do the rica. As I did not know what kind of phone this was I opened the box and decided I did not want it. I called call direct but they said they would not take it back because it was opened and the person who delivered the phone had told me the terms and conditions. I told them that I did not meet anyone from their company as they had left the phone in the reception. I was then told that because I did not meet the driver, they would lodge a dispute and get back to me. This did not happen until I called them twice. Today I spoke an arrogant Randall Muller who told me that they are not taking the phone back because I was told by the sales consultant that if the box is opened they will not take it back, I requested the call which he sent and nowhere is it mentioned that if the box is opened they will not take the phone back. His response when I pointed this out to him was that I shouldn't have agreed tot he contract if I didn't want it. I don't want this phone anymore and I demand that Sell direct take it back because they did not tell me that I cannot open it if I'm going to change my mind about it.