Unauthorised debits becoming my problem

I used to get money from friends and relatives who'd just deposit the little money they could afford and it was always less than R300. Later on they stopped and there was no movement in my bank account and the bank froze my account and said I should submit a proof of residence letter in order to activate my account. On Friday 12 February 2016 I took the letter to the Morimolle branch and the lady who helped me also printed out a 3 months' bank statement for me. When I get home, I realised that I had some money in my account and the bank allowed ****s to debit it from my account until I was left with R66.26. These ****** where debiting R89 each time and I wasn't getting sms's to inform me that my money was going out because it was less than R100. I went back to the bank on Saturday and was assisted by Francinah. I told her that I want my money back and she said ai can't get it back coz the debits have passed 40days therefore they cannot be reversed. There was only one debit of R89.95 which she said she can reverse but will have to charge me R20 for the reversal. I don't understand why the bank charges us when they're the ones allowing people to take our money without our permission!