You’ve probably been phished.

What these scammers do is send out thousands of emails to random email addresses saying something like ‘double check your flight details’. Inevitably someone clicks on a link or calls a phone number in the email, and hands over their personal details which the scammers use to take control of your ticket.

If you have a Krisflyer account linked to your ticket, I’d suggest changing your passwords and security questions etc. before they clean out your miles as well.