Cell C de*****ed me

My name is Sibongiseni Mkhize. I had a 24 month contract with cell c of R188 from March 2013 so it was going to expire end of March 2015. Around December 2014 the store started calling me informing me that my contract is due for an upgrade but I declined. At the end of March 2015 I saw that Cell c made a debit order of R500 when I called customer care they told me I made an upgrade at Umlazi Megacity when I get there they asked for bank statement and an affidavit stating I did not make the upgrade so they can send it to quality logistics or something and opened a ***** case so I did that. At the end of April another debit order was made this time for +R1000 went back to the store they told me they are still waiting for the copy of my contract from quality logistics so they've been telling me the same thing ever since. Now thanks to Cell C I have a bad credit because I had to block them from making those debit orders now I get declined for every credit account I try to open. They can even get me a copy of that upgrade contract so basically they can't show me what I'm paying for. I hate cell c for what they did to me.