Google-calendar – Google calendar: events disappeared after I edited the calendar

Your calendar behaves this way because of the settings in Google Apps. The default config for sharing outside of the organization is showing only free/busy information without the details. Your admin needs to change it to Share all information, but outsiders cannot change calendars or Share all information, and outsiders can change calendars in the settings page of Calendar (simply click Calendar from the admin dashboard).

You can also try setting each of your events as Public when creating them. That's the option in the Privacy control (the very last one) on the event creation page. However, this might not work because of the organization-wide setting described above.

Try what you've proposed: delete the calendar by going to Settings -> Calendars and unsubscribe / delete. Then re-add it to GCalendar. I'd seek support with RTM (they're the ones pushing events to that calendar, plus you have a PRO account).