この前 = before
違えて伝えて mistakenly told / told by mistake
しまった = accidentally
事がある = there's something
会社で、この言い方を使えます。
I'm sorry, but it turns out I told you something wrong by mistake.
I'm afraid I mistakenly gave you the wrong information last week.
日常会話の場合、これを使ってみてくださいね。
Remember when I told you XX? Well, actually, it's YY.
I think I may have told you the wrong thing before.