Import a SharePoint 2007 Calendar into Office 365 Shared Mailbox

We have an older onsite SharePoint 2007 installation that has about 3 calendars that are connected to Outlook. I can export these as several formats (pst, csv, Excel list). I'm trying to then re-import these into a shared Office 365 calendar as we're no longer utilizing SharePoint. Doesn't matter if I try adding these through Outlook to the calendar, OWA, or PS. I can't seem to get the data imported either without an error message or nothing at all, just a blank calendar.

Any suggestions?