Wont pay back a debit order, even though I paid for 2 months in advance

I have thee worst luck with this Bank, I swear. I have a loan with them, I was told if I want to pay ahead, I can do so via the App and choose "adchoc " payment. I paid 2 months in advance, for the month of November and December, however the debit order still came through the month of November, meaning now is 3 months worth of payment made. I contact them to ask that they reverse the debit order, seeing that I have paid for the Month of November already. I am told choosing the adhoc payment gives them a right to still debit my account, this is NOT what I was told by one of their consultants, I laid a complaint and explained that I desperately needed that money back. They keep telling me its been escalated, its the second week now and the money is still not in my account. I need the money for my daughter and they dont even care. be in arrears for one month and they will take whatever money that is in your account, but when you need your money back they take forever to just put it back. I am disgusted by this bank.