double debits

I have been with african bank for 5yrs now and I'm very disappointed to the service render lately,my loan debit order went off twice this week leaving my account in arrears, my bank now charged me for falling debit orders after getting an sms confirming a second debit I then called your customer service I spoke to a lady by the name mahlatsi she was not helpful this is unacceptable really can someone give me a clarity on this matter and fix,reverse that debit order immediately and I want to be refunded with those bank charges aswell....thank you hope to hear from asap