Bad customer service

I have a personal loan with FNB and I notice that my debits were not going off like it supposed to I tried calling them numerous times. But didn't succeed because you stay on the line forever whilst the music plays in the background and your airtime just running out,then I tried email that also didn't work. So now my account has gone behind and low and behold what happens today,without any warning they deduct the arrears without any warning or making payment arrangements. Now I am sitting with the problem of not having money to pay for my rent and to provide for my family due to FNB consultants being in competent and when you finally get hold of them they going to tell you that there is nothing that they can do about it. The funny thing is that it is always going to be behind because no matter how many times I called in to correct the debit order dates they still get it wrong. So now I must try and call them with airtime that I don't have and I can't even take off to go into a branch.