Terrible service form FNB Private banker

I asked FNB private banker to close a debit order on my account....they responded and said it was closed. I realized then that after 3 days my account was debited. I emailed them they took long to respond and after further pressing then they responded saying they cant stop a debit order. what nonsense is that, why they **** in the first place and why they not responding to may mails.