Unauthorised Amount Deducted Again

I have a payment arrangement with FNB loans Consumer legal that on the 25th of each month they deduct R1747.03. I regularly pay every month, but this month they deducted twice without any consent or arrangement. I have had this issue before wih FNB and they wont reverse the money over the phone. You just get pushed from one department to another saying they not allowed to reverse the money, then holding on the line at least 30 minutes per department. Please can a Manager phone me urgently regarding this. I need that amount reversed ASAP, as I have rent to pay and cannot afford double my installment to be deducted this month. My cell number ********** or work number **********