unfair billing

Cellc cancelled my contract and provided me with cancellation DOC SD632002. They keep on putting d/o through, I keep on reversing them, they then just use another ref nr and put through ridiculous amounts, that to me is *****. I have spoken to so many staff members but they are soooooooooooo ***********, don't have a clue what they are doing. Can I take them to court as a last result, as they are ******** and I have reported them before to Hello peter, but they are not responding. What is the use of sending me a doc nr but they still put money through. THEY CANCELLED THE CONTRACT AS THEY CANNOT FIND THE PROBLEM OF WHY I DO NOT HAVE COVER!!!!