Vodacom contracts

I will never recommend any one to ever have a contract with vodacom. Up untill know after a year and a half they still claim I owe them money. I paid my contract every month as per the amount that was due on my invoice. The one month they claimed I never paid the prev month but I did I have showed them the proof and then they reconized they made a mistake on the system. I paid every single month untill my contract have ended . Now they have put me in bad credit record.