[273-70] Help my friend negotiate with the Bankwest

My friend wanted to transfer her money from Bankwest in Australia to Bank of China in China. She transferred it for many times, but she found she got the USD from the Bankwest this time, and she suffered from the exchange loss about 200 AUD.

She signed the applied form without tick, then she came back to talk to the bank teller to change it after few minutes. The bank teller said it was ok to change it. About a week later, my friend got the USD, not the AUD. She wanted to know what happened. Why the bank teller said it was OK, but she still needed to suffer from the exchange loss and got the USD. My friend's English skill is not very well, and she even doesn't know how to say from A to Z., And she only knows few English words. She tried to use the copy of the international transfer form that she did successfully last time to ask the bank teller to help her to apply another transfer form. When the bank teller finished it, just tell my friend sign it, and she didn't check it again then sign it. When we try to negotiate with the Bankwest, they just said my friend already sign it, and that means my friend was happy to accept everything. When we said that my friend came back to confirm this problem in few minutes, and the bank teller said it's OK, and she will helped my friend to tick it. However, today the Bankwest said you can't trust anyone, and you signed it without tick the "Do Not Convert" check box, that means you was happy to accept it. How can we accept this answer and how can we trust the Bankwest?