Suspended line and Credit rating

I had a outstanding debit with Telkom of the amount of R1569.40 which i have paid via direct debit however they still say they have not received the payment. my line is still suspended and i still cant get any credit as my name has been listed. i have made several calls to the call center and they always advise me to go to store and when in store i am always advised to call the call center. i have also tried to make contact with NuDebt which is their collections agency with no luck as well. this has caused so much inconvenience in my life as i cannot receive any credit to purchase my car. PLEASE HELP.