I am receiving spam messages in my calendar app.

Hello , i today suddenly started receiving spam messages on my calendar app .

it be like " today at 2:00 pm your iphone will be easy to hack for hackers ..etc" .

I understand nothing in technology and i am frightened that they're stealing my data , so my first question is will they be able to steal my data ?

i read many articles on how to get rid of it but nothing worked i am neither able to delete the calendar from the calendar app nor report it.

it is placed in the " fetch new data " category in settings and I can't delete it by any way , please help me i'm so concerned.