Debit order with no fund's

So I have been retrenched struggling to make payments. Busy completing claim forms. Nedbank just goes and takes money out my account. No warning. How am I to survive. I need to put food on a table. My account now goes into a negative. I get charged R150 for a return. Which I need to pay. Unacceptable. I want to close all my accounts. How can you do this to people. I had to loan money from ppl to try and pay rent. APO MANUAL PAY ********** ********** 50. What happens now. Your charges are exorbitant. This is ridiculous.