REFUSING TO PROVIDE STATEMENT AS I WAS BILLED INCORRECTLY!!!!!

Took a personal loan for 24 months and as per statement for October 2017 outstanding balance was R2605.14,debit order in November and do my knowledge last installment including interest was supposed to be in December but no they continued to debit my account also this month,. I called call center spoke to Zakithi Mpinga she could not explain ,asked for a statement even now im still waiting !!!!!! I want feedback urgently as i was billed incorrectly and i want my money.