Coldest bank - ******

I dont even know where to start. I was double debited on the 15 Dec for a loan that is due to be paid on the 25th. The first debit order was the installment and the second was arrears. This is bearing in mind that i made arrangements with the bank on a monthly basis to make arraignments. On this particular month they decided to call me on my work number (im working from home) vs all the other months they would call me on my cell. My request when i went to the bank was to reverse the second debit order. They refused informing me that they can only give me half from the second amount... Do i not have a right as a customer to be allowed to make arraignments on my account? Why does the bank not allow me freedom to handle my finances as i see fit, allow me to make arraignments as i always do. Not take my money then refuse to give it back even though the current installment debit order went off? When at the Festival mall branch they called a manager to assist, who called the regional manager who called complaints as credit was refusing to refund me my money...today again i was called by the complaints department to inform me of what i was already told that i will get half. Whats even more concerning is the cold type of service you receive as a customer, no empathy shown what so ever...