Merge calenders

I did this (exporting calendars, create new calendars, import old data, delete old calendars). Not only do all the old calendars still appear in my third-party to-do apps (which I can't delete), but worse, all my new calendar events disappeared once they were uploaded to iCloud. All my events and reminders are gone from my iCal month sheets. This is completely counter-intuitive.

Any ideas on making iCloud respect these calendars so they appear again (before I miss an appointment)?