Spam Calendar - Fetch New Data

I had spam events in my calendar, I unsubscribed but the event still shows up in my calendars, I cannot delete it completely. Also, I have deleted calendar accounts from my phone in settings>calendar>accounts, however, when going to settings>calendar>accounts>fetch new data, the spam account is there and there is no way to delete it. There have been previous discussions on this topic but none of these give a solution on how to delete this completely and remove it.