Disgusted with FNB

I am very disappointed with FNB bank... I have held my account with FNB for over 15 years I have all my banking with them personal account, business account, saving accounts as well as personal loan. I fell into some financial difficulty about 6 months ago ans could not keep to my commitment on the loan installments, I then explained to FNB that I could only start repaying again in January as I am now getting my footing back financially. On the 22nd of December I came into a bonus amount of cash from work which I transferred to my savings account because I need to pay my bond, vehicle, electricity bills, school fees and buy uniforms and stationary as I have 2 kids in school and one entering high school which requires fees paid upfront. I was at peace knowing I had this amount to cover me for these important bills for January. Today I woke up and was horrified to see that FNB had transferred R17000 out of my savings and took it for the personal loan which was in arrears. I had absolutely no notice or warning of this as far as I knew my arrangement was to pay end of January. I am in absolute shock and so heart broken. How do I pay my bond and vehicle and electricity expenses, how do I send my kids to school in a couple of weeks. Am I supposed to lose my house and not put my kids in school because of FNB. How can they just have the right to take my savings without knowing what it is for or why it is there? I do not advise anybody to keep savings accounts or current accounts with FNB because should you come into any financial difficulty they will help themselves to the little you have left instead of allowing you to pay the debt off via an AOD. I will definitely be taking this issue further as I want these funds back.