Debit order reversal

Good day, I have been trying on the FNB app to reverse a debit order, I have always been able to, but now it’s gining me an error “Debit order cannot be disputed” then prompts me to select money assist, but I am unsure of the money assist feature, will it eeverse and block the debit order etc, I have tried to call in but the lines are busy, been holding for over 25 min..can someone please assist me..