Poor service provider

My problems with my bank started on Tuesday my bank balance was R150.00 plus a few cents then before I knew it R2000.00 rand extra was reflecting on my account. On Wednesday the R2000.00 was still in my account, I then moved the R2000.00 to my savings pocket just to monitor my account as the amount was not reflecting on my transaction history. On Thursday I still had my balance of R150.00 and I transferred R300.00 from my savings pocket into my cheque account and went shopping. On Friday I transferred yet again R900.00 and and went shopping and bought petrol. I had a balance of R200.00 on my account on Saturday when I was paying for petrol my card declined only to find that my account is on a -R1800.00 the bank then charged me R150.00 saying I bought petrol on the 19th April when I had insufficient funds in my account but it's not true because I bought petrol on the 16th April and I had funds. I was again charged R150.00 for when my card declined on the 17th April and my card declined. I really don't understand this, I spoke to the Bank but I didn't get help. The consultant left the chat without assisting me. Please help I need my money back, I can't even transfer money into my account because it goes away soon as it reflects.