Formal to Client
Workplace · Phone
You
申し訳ございません。こちらは○○株式会社でございます。お間違いではないでしょうか。
もうしわけございません。こちらは○○かぶしきがいしゃでございます。おまちがいではないでしょうか。
I'm very sorry, but this is [company name]. I believe you may have reached the wrong number.
Romaji: Moushiwake gozaimasen. Kochira wa [company]-kabushiki-gaisha de gozaimasu. Omachigai de wa nai deshou ka. / Reply Romaji: A, sumimasen. Machigaemashita.
Reply
あ、すみません。間違えました。
あ、すみません。まちがえました。
Oh, I'm sorry. I have the wrong number.
Gesture & etiquette
(Phone) Keep your tone warm and unhurried. If the caller seems confused, offer to help them find the correct number if you know it: 'Dochira ni okake ni naritakatta no deshou ka?' (Who were you trying to reach?)
Always begin with an apology ('moushiwake gozaimasen') even when the caller made the mistake — in Japanese service culture, the company's role is to help, and a wrong number is a chance to do so graciously. Never hang up abruptly.