You guys messed up my credit score!

During lockdown I made an arrangement to pay a lessor installment on my personal loan. From the time I made the payment arrangement I was debited the arranged amount, the actual installment and then another amount to make the the arrears of the actual installment. I had to call in every month to get the installment that was not meant to go off refunded. I now find out that nedbank has listed me on ITC for missed payments! I had never missed a single payment I only requested the additional amounts that were being debited to be refunded. I am so freaken upset! I worked so hard to get my credit record up and nedbank does this??? I moved all my business from fnb to you guys and I'm starting to deeply regret it!