Bad service, I need my refund

I used my fnb card to purchased a weekly trip on 16th of April unfortunately I was charged twice but the gautrain cards has only 5 days which I showed the customer service lady's at the station who advised me to lodge a refund online which I did, throughout the whole weeks I was following up with them only to be told to wait for 14 days .and today I checked the status of my claim it stated that it has been rejected, with no reason .surely they can see that the money went into their account twice on the day .if not why can't they ask me to produce proof from my bank .and I need Mt money I am no longer waiting for 14 days tell me what you need from me to assist with this process. I need answers immediately