I am afraid that I had made a deposit in online booking, but paid the full amount. I would highly appreciate it if you would kindly check my records to reimburse the amount equivalent to the advance payment.
I have already prepaid a deposit online. If you could reimburse me the difference, it would be much appreciated
こういう場合にshort and sweetがいいですね。
「I have already prepaid a deposit online」オンラインデポジットも払った.「 If you could」してくれれば嬉しんですが「 reimburse me the difference,」払いすぎた分を返済して「 it would be much appreciated」くれたら助かります。
日本 
オーストラリア 
