Unfairly debited

Hi guys,I have a problem with Atlas finance in Pretoria, andries street,they took 3 months installments without my go ahead in December,and they ddnt wanna refund me.those payment were the last 3 payments that I had to pay..so now they took another payment and i do not owe them anymore,please help me to get my money,those guys are useless when coming to solving issues,their head office is the worst they don't even respond to calls