FNB don't care

I informed FNB, that I won't get paid by my employer at the end of April 2020. I app**** for Covid 19 relief and uploaded the letter from my employer stating that I won't receive a salary. FNB approved my application. On the 30.04.2020, FNB processed a string of debit orders on my zero balance account, causing me to go into overdraft. They are now sending me messages asking me to deposit money, to rectify the overdrawn amount. Where must I get the money from? FNB knows my current situation. I tried to reverse the debit order on the Covid 19 function, and was told by Shanil on the secure chat app, that FNB has stopped the debit order reversal function on secure chat platform. Why now? I feel desperate and helpless and feel that FNB don't care. I emailed my personal banker to ask her not to let any debits go off, and sent her a copy of the letter from my employer, but I had no response. Wendy Malgas