No assistance with early debit orders

I'm not sure what the point of the new Debbi Check mandates are for when FNB still allows people to debit accounts as they want and then refuse to assist. HI-FI Corporate debited my account 2 weeks before the agreed debit order date. I contacted Hifi corporation people and they ignored me so I contacted my bank and their call centre gave me the runaround for an Hour until I gave up. I think they transfer me to every department in FNB and some departments even 3 or 4 times I have screen shots to prove it. I'm getting really disheartened with FNB, I have put Millions through their bank in the last few years but they can't assist me with a simple query.