After 10 years still cant sort out their accounts!

I recently paid R15000 on my Woolworths account (never missed a payment, but wanted to pay off my account) and got a call the next month saying that I missed a R105 payment and that they were authorized to give this information to the national credit bureau. When I asked for a reference number to the call I was told there is none and was rudely asked when I will pay the R105. Previously I paid R25000 on my account and they reported to the credit bureau that I did not pay them R50 the next month. When I ask to escalate the issue, I am told that their finance department is outsourced.