Charged interest on a Settled loan account!!!

I am very unhappy with FNB!!!! I called the contact centre and checked on my FNB app for my settlement amount on a personal loan on the 15th Jan, on the 16th I settled my account and received a statement 31 Jan 2020 with a zero balance. I assumed this account had been closed as this was on a zero balance and had been settled. I received a statement with a balance owing to FNB for interest. I find this so unprofessional and in many ways terrible customer experience. FNB boasts of being innovative but don't have a seamless or streamlined process that identifies accounts that have been settled and close these accordingly!!

I am so disappointed with FNB, I expected much better from a so-called Future Forward organisation.