Depressing Calls and sms's

On the 1st of August 2014 I paid Queenspark account with an amount of R200.From my understanding after that amount I'm suppose to be owing nothing in this shop.I received a call reminding me to pay Queenspark.I told the person who called me that I've paid already and she told me that it doesn't appear in their system so I must go to the bank and inquiry.I did and I got the proof of my payment and faxed it to RCS and Queenspark.They acknowledged the receipt of my payment.Until now my account is not updated yet and i'm receiving calls that says I'm owing R490.00.When I ask them why am I owing such amount they told me that it's because of the calls that I'm receiving from them.I don't understand why they are charging me for the calls even though it's their responsibility to update customers payments.Please help because this is stressing me .Yesterday they threatned me to hand over my account to Credit Bureau.I also received an sms saying that my account is being updated on XDS a registered Credit Bureau.They gave me this number to call:*** .I did and they told me the same story of owing Queenspark.Thank you.Nomanesi Sitoto.