THEY RUINED MY CREDIT RECORD AND DEMAND MORE MONEY!!!

THEY RUINED MY CREDIT SCORE!!! In July of this year i wanted to cancell all of my contracts with Vodacom as the were supposed to but they wanted me to pay 4 extra months wich i did not want to do so i paid the cancelation fee and everything was sorted, today after 4 months they sent me a summons thay i owe them R736 and the last statement they sent me was in August that showed my balance is zero, i missed one payment in april, when i checked my credit score it plummeted becuase they said that i haven't paid them for the past 4 months so now my credit report says that i have 5 missed payment, and i cant dispute it only they can, so now not only have they made me pay 40 months on a 36 month contract they also ruined my credit report and demand more money after my accounts was closed 4 months ago