Ask HN: Emails from MS about account with almost my address. What happened?

I got a series of emails from Microsoft to a slightly misspelled address (firstlast@gmail instead of first.last@gmail)

Email 1) Cofirm your email address Email 2) Your account has been renamed Email 3) Your account has been activated Email 4) Game purchase order

It seems my email haven't been breached (I have 2fa and got no prompt). My Microsoft account first.last@gmail doesn't show any activity. I haven't been charged anything.

The credit card used in the purchase order doesn't match any of my cards.

I have contacted Microsoft Support and only got to the first level support who were able to confirm that the emails are legit from Microsoft (based on headers, domains and signatures) but were unable to tell anything about the order / account itself.

I wonder what has happened and whether I should be worried.