Communistic Institution

Nedbank sent a SMS a while ago to request that I move my December debit order date earlier. I recall responding with keeping the date as is and TO NOT change the debit order date. I still have it on my phone as proof.They disregarded my request and two installments were deducted from my account, meaning I am left with almost nothing of my December salary. What am I supposed to eat and how am I supposed to get through the rest of the month? Nothing was arranged with me and who gave this institution the right to take my hard earned money? I am a good payer and is how you reward me? They obviously need money to pay golfers and care more for their public image than that of their clients. How long before they will refund the 2nd payment? How will I know for sure another payment isn't scheduled the normal date at month end?