Unfair charges

2 August 2023, I requested a settlement amount of my 12 months loan. I was given an amount of R712, I made an immediate payment on the same day since the settlement was valid for 1 day. Payment reflected later the same day, on the 3rd of Aug I checked my account, to my surprise I was charged late payment fee, then suddenly I owed R126, I called client services make a follow up the consultant confirmed I was not supposed to be charged, she then transferred me to finance so they can update my account. The lady advised me to send proof of payment, which I did 5 minutes later, I received an email that my account has been updated. Today, I. Checked my account, another late payment fee is charged and I am now owing R206. Why am I being charged because I paid off my loan?