Unaffordable overdraft

I lost my job in February and took my dismissal letter to the bank to make arrangements for my personal loan. FNB offered me a overdraft of R35000. How can a peson with no job afford a loan like that? Is all loans not subject to affordability? Any case I was told that an overdraft you can pay back as you have money and that only R85 per month will be deducted from my account. During the last few months fnb has taken money as they wish with no prior notice. This month they have reserved R5600 which was supposed to be in the account for my debit orders and utility bill. All my debit orders returned and the bank cost on that is more than R1000. There is so many mistakes made the last few months, there will not be enough space for all my complaints. Anyway I keep on sending emails and via email has been assured that fnb will call me back. I keep on asking that they please contact my wife as I am not available during office hour but also to no avail. I am in huge debt because of these mistakes made by fnb and they take no measures to correct them. I have already made a case with the ombudsman.