What do I do if someone hacked my calendar?

That is a Rogue Calendar account. Go to Settings ➔ Passwords & Accounts and under Accounts see if an unknown calendar account is listed. If it is then tap on it and then Delete account.

Note that it is not a virus or a hack. It is something that got added to your calendar because you may have accepted an offer from a pop-up on a website unknowingly. Please be careful out there,

Good Luck.

Axel F

You calendar is not hacked. What makes you think that it is hacked? Let us know with details and we can try and help you out.

Axel F.

You are welcome.

Axel F.