Duplicate debit order

So December I thought I would be proactive and ask for my debit order to happen earlier. Can imagine my humor to get billed twice, especially when I'm in another country. When I tried calling to discuss the first account person imp**** I was mistaken and had no clue how the payments work. I was told this would be investigated and they would come back to me. Surprise no call. Still not resolved I called I called yet again.. after being told I was mistaken. It was followed by a oh actually you right and would you like to be refunded or would you like a credit. Early January - please refund me. A third time now.. I am being told a credit note will be raised and I will be reimbursed on Wednesday as payment runs take place on Tuesday. As a customer I feel incredibly frustrated and inconvenienced as I have had to make continual calls to resolve something so simple. Why do I have to get upset and lose my mind with someone who probably doesn't deserve it because of their fellow employees not doing what they supposed to. Thank you to Palesa for assistance and enduring my irritation but I am hesitant to be grateful until I am refunded.