FNB not acting in good faith

FNB Card Department has flagged me as a HIGH Risk client saying that FNB Card wrote off bad debt for the amount of R 56,000 odd rand's.

A Mrs. Bernadette at FNB card division whom is fami**** with this is been reluctant to produce the documents an evidence relating to this.

her mail is as follows: I tried calling on your cell 072 …………….. no answer please note we confirm that whilst the Bank is not pursuing the recovery of the debts due to prescription and as a result of the losses incurred by the Bank, an internal indicator was captured on your profile and will remain.

I have requested proof of this debt on numerous times, been shipped from department to department. I now need FNB to act professionally and produce the documents so that either can settle this debt if it true alternatively FNB need to clear the risk factor listed on my name