Very bad service

I ve settle my loan account with my FNB banking app by a direct transfer from my account to my loan account. as Wesbank(Directaxis) is connected, The transfer was made on 22nd of January 2021 it shows that my loan is 0 The 1st of February 2021 they deborder went off my account with the life cover they provide I call them told them that this loan has paid up in full. They told me that Must sent them proof of payment FNB said the interbank linked so they must pick up the payment because on a direct transfer you got no proof of payment FNB sees the transfer and Wes bank must be able to see it to. So now I'm paying double on a settle loan with all the interest and the life cover that they provided. and no body in Direct Axis or FNB can solve this matter. What to do please if anyone can assisted. This is really a matter that I some how must sort out.