R6166.72 DEBITED FROM MY ACCOUNT WITHOUT GIVING PERMISSION

On the 25 of Jan 2019 debit order for R5144.90 went off my account I don't even have any debit order with FNB for such huge amount . I went to Menlyn branch to dispute it I was connected with call centre , I spoke to Sanele who said I cannot get my money back because I used to have a loan with FNB long time ago , I told him I do agree but I was about to make arrangements since I re-activated my account in October. He said FNB will refund me and It wont be within 7 days because I made a new arrangement with him for R500 starting form 25th of February 2019. He told me that sir you will get your refund they will prioritise it because I made new arrangement. The following day on the 26th I got another notification that FNB debited me R1021.82. This morning 28 Jan I went back to FNB Menlyn I was connected again to call centre for dispute . I spoke to Khethiwe she told me that I cannot get any refund on both debit orders. I was told that Sanele gave me false information. I even requested to speak to Sanele who told me that he gave me wrong information and he apologise. Khethiwe and Sanele also metioned that they can only motivate with their admin in order for me to get at least R2000 . I have so many responsibilities and commitments with my hard earned cash . Sanele also told me that he will get his manager to contact me , I ask him what time, he said now that was around 10;30 since 10:30 I am still waiting for FNB to contact me but to no avail. I was told that I have been on the call for 40mintunes he want to assist other clients I must end the call. I want my money back I cannot afford to be debited more than R6000 without giving FNB permission to debit my account with 2 different instalments. can someone please contact me ********** 098 to resolve this matter. I trusted FNB with my money and now this is all that's happening into my account , whenever they feel like going it to my account they just go and debit any amount that comes into their mind . I really want to know who authorised those 2 debit orders.