I am being billed for a contract i don't have

I took a new contract with cell c in May i spoke to Godfrey Hlongwane who sold me 2 contract i then accepted , the first phone was delivered and the second phone was delivered a week later but when the courier guy came do deliver the 2nd phone he had an extra phone with him for me which i told him i will not accept because i did not request and asked him to send it back, which he did on the same day of delivery i called Cell c to advise them that the courier guy had an extra phone which i did not take and i send it back, they told me it was just an error on their side all we be well, weeks later i find out i have 3 contracts with Cell C instead of 2 I have been trying to get a hold of Cell C the call center agents are mean and horrible they don't want to assist, they are not willing to even listen they push from one department to the other, i then went to their Cell c store in green stone i was still not helped , i called again then i spoke to a lady by the name of Mokgaritsi she did try to help but things are still dragging . the initial contract was supposed to be R 210 p/m but i was debited R455. i need help please