Hey Chris,
Welcome back and sorry to hear you’re having troubles. I would recommend checking out the Bulk Delete plugin to help clean up the deleted events. Let me know if this solution helps.
As for stopping the CSV import while it’s importing; I’m not really sure about this one. I’ll be sure to ask some other support team members if they have any ideas as I wasn’t able to find any examples of it being done in past threads.
Once I hear back about how the Bulk Delete plugin works, I should have an answer for you about stopping the CSV import. To request a “stop import” feature, please head over to our UserVoice Feature Ideas and submit/upvote the idea there.
Have a great weekend ahead and take care. Cheers!