お困りですね。ChatGPT に一部加筆しました。 URGENT! Subject: Request for Immediate Cancellation of Unauthorized Account To whom it may concern, I am writing to request the immediate cancellation of an account linked to the following card number, as I believe it has been used fraudulently. Please note the following: I do not recall entering into any contract with your company. It appears that my information may have been used without my authorization. As I have no memory of registering with your service, I do not have any details such as the account holder’s name, email address, or other account information. Given these circumstances, I kindly request your urgent assistance in canceling the account linked to the card number below. [Card Number: XXXX-XXXX-XXXX-XXXX] I would appreciate your prompt attention to this matter. Please let me know if any further information is required from my side. Thank you. Best regards, [Your Full Name] [Your Contact Information] (メールアドレスなど)