Agreement not met by bank

I was indebted to African Bank. An agreement was made that if I settle the debt by 31 December 2021, then I will receive a 30% discount on the debt. They sent me settlement letters stating the amount that needed to be paid and the due date.

I paid the total of the debt on the said date,as per the letter from African Bank. When I asked for a statement too see that I now owe nothing, it was still showing that I owed money.

When I contacted them it was said that because the money only reflected in their account 3 days later, it still showed that I owed the balance of the debt.

As far as I am concerned my debt is paid up to date as I paid the total as stipulated by African Bank on the debt mentioned by them. They should have looked on my profile to see if there was any arrangement made before allocating the money to my debt and then they would have seeing the letter on my profile.

Obviously the correct procedure was not followed by them. I even sent the proof of payment which shows the date the payment was made, and they still got it wrong.

Will take it further if I have to.