Standard bank loan repayment

Took a loan with Standard bank some few years ago this past month they took double the repayment amount and I went to the bank to report it they looked and said it would be reversed as I was on track with all my payments. A week passes and I call them they say I didnt pay some month back and I ask for my statement they give me a hard time with it. Now they giving me the run around and won't give me back my money as promised