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The Calendar that comes with the purchase of a Workspace Email plan renews independently like other GoDaddy products. If auto-renew was no longer on the product, or there was a billing failure for the renewal, the product will expire out of the account. If the calendar was removed recently, we'd encourage you to contact our customer support to see if it can be restored.
Our unlimited group calendar is set to expire 6/30/2020. I contacted customer support and they basically informed me the calendar health was not workspaces responsibility to monitor. There was no trace of any data or history of the calendar missing and there was no issue. They could not retrieve any of my data.