Paid off account but got reported to credit bureau!

Rage is destroying my credit score! I received notification that I owed R103 or so on my Rage account. I will admit that I did not immediately attend to it as I had recently received a cesarean section and was still on bed rest. I finally attended to making payment and my account was paid in full after making this payment. Notwithstanding, Rage has reported me to the credit bureau and now I cannot open my account with Investec! They are ruining my life over R100 rands! Whats worse is when I call head office to sort it out I no one picks up the phone!! Rage update my records immediately I do not owe your store one dime!