This morning while I was sailing in safari I skipped several pages of advertisements, in one of them I got a pop-up notice to subscribe to your events; My bad luck was to give the option to subscribe by mistake and then several events were created in my calendars; Try to erase the events and the calendar but I could not, look for information online and more of the same, restore the device completely and nothing. Well, once all this was done I started to think, since for a calendar to be created, a new account must always be created. Well, I went to the option of settings, passwords and accounts and there a new account appeared that was not mine, which had created the happy calendar subscribed in the app. After deleting that account, the calendar with the spam events disappeared from the calendar application.
I hope this information is useful in case the same happens to you.