there was a mistake in recording the amount of money
「金額の記入漏れ」は英語で「an amount of money was omitted」や「there was a mistake in recording the amount of money」といいます。
I'm sorry for the mistake in recording the amount of money.
（金額の記入漏れがあってすみません。）
Please try not to make mistakes when recording the amount of money.
（金額の記入漏れのないようにしましょう。）
イギリス 
