My iPhone has been hacked Everything is saved on iCloud Wot should I do?

Ok. You’re getting spam messages. You haven’t been hacked.

open calendar

go to calendars (to see all your calendars)

look under subscribed calendars

you’ll likely find at least one you don’t recognize. https://support.apple.com/en-us/HT211076

for messages, start here https://support.apple.com/en-ca/guide/iphone/iph203ab0be4/ios

It's unlikely your phone was hacked. But, if it makes you feel better you can do it. Vist https://support.apple.com/en-us/HT204184