Outlook for MAC- Deleting a Meeting Invite since account is closed

I no longer have an email address associated with my outlook account as the company closed and the email address is no longer active. When I removed the account it deleted most of the meeting invites but has left 3 reoccurring appointments. I have tried deleting them on numerous occasions and it looks like they are deleted until I close out of the program and then go back into it. Every week I get three reminders of meetings that no longer exist and it is driving me crazy. Please advise on how these can be deleted.