Calendar Spam/virus

I was watching a series online and an ad popped up that was obviously a virus and accidentally clicked something that subscribed me to a calendar of some sort. since then, ive been getting notifications in my calendar that are clearly spam, and when i go to delete the calendar subscription or even the events themselves, theres no delete button or anything of the sort.

i've managed to stop the alerts from coming, the events are still popping up in my calendar. i've looke at icloud online on my desktop too and the events nor the calendar subscription show up there.