Very disappointing Private banking experience

I received numerous messages from FNB offering me discounts on early settlement of my loan and credit card. When I required, a settlement letter was sent to me. I had then made the payment and when enquiring about how long it would take to obtain a paid up letter, a consultant mentioned that the balance may be written off as bad debt, negatively affecting my credit score. I would like to know why this was never communicated to me on the settlement letter where the discounts were indicated, and why FNB would offer a discount to customers if there are negative implications. I have paid all my accounts based on the discounted amount as I am trying to purchase another property. All of this effort to increase my affordability, only to find out that my credit rating may impact my application. I am tired of trying to contact the bank. They transfer you from department to department and keep you on hold for lengthy periods of time, with no resolution at the end. I am very disappointed, especially considering that I am a Private Client.