FNB stole my money / unauthorized deduction

FNB deducted Money from my Pocket Save without my permission nor my authorization. In 2016 December they deducted just over R5000 without my consent and I went to the branch I was told they won't be able to get the money back and they suggested I open a pocket save account to keep my money in and no one would be able to deduct a penny . At the time it's December rent is due , I still had to pay school registration for the little one but through God's grace I managed to make it through that tough period

Today again (February 2018) they deducted R900 from The Pocket Savings Account (The one they suggested I put my money in and no one would be able to deduct) without any authorization. Called my debitors and let them know that I've recently lost my Job and I have arrangements in place to pay , and the agreement I have with FNB says nothing about them Deducting my last penny without my consent basically they stole my money from my account I mean who gave them permission to deduct? Who sent them to take it ? Isn't that *****ing ?