Joke from Citibank

I wondered is it because today is April fools' day or the citibank decides to play a joke on me.

I have recieved the citibank statement today. I remembered I have booked and cancelled Countrylink, an online Australian train transaction, just a few days ago. According to the Countrylink, once i cancelled my transaction, it says that it will fully refund me the payment. However, the citibank has charged me $30.

Therefore, I called up Citibank to find out what is going on. The customer service person told me immediately that I have to pay that $30 because it was due to the transfer currency rates.

I was unsatisfied with that answer. I questioned him "I was told from Countrylink that it will refund me the payment fully. How could Citibank charge me something that was cancelled?"

He quickly tells me that he needs to check with the higher authority.

After a couple of mins, he told me that it is not my fault but I need to fill up "Card holder letter of dispute" so that they could waive off the discrepency.

I was thinking If I had kept quietly, probably I will be a fool to paid Citibank a transaction that was not even processed at all.