FNB Debit Order Reversals

I writing this regarding my debit orders that cannot be reversed by FNB. I made arrangements with African Bank regarding the payment but to my surprise they debited R886.64 twice total is R1777 and asked FNB as I am banking with them to reverse both debit orders they tell me they can't I have to call African bank..First of all I do not bank with African bank. So please kindly reverse those debit orders as soon as possible..I want my money into my bank account within today..please..How can FNB stop reversing them during this difficult times of COVID19..If you don't reverse them I am escalating this matter further. I called them and even visit their nearest branch there is no assistance....They say they cannot reverse them anymore..why??