Google Calendar Gone

Sorry I wasn't specific enough I was in a rush and had a crying family member I had to inform that they more than likely lost their entire work schedule for the last few years.

They were using a third party app (Tiny Calendar) on iPhone 6 and upgraded the version. After the sync they have nothing. It is set to sync with Google Calendar. We logged into Google and the calendar exists but no entries. I tried hours worth of online suggestions to include sharing it out to see if another can see. Without Google calendar showing any data I fear they may have sync'd a blank. But app didn't have any settings to overwrite and be first choice (kind of like how ACT can be the first position in a conflict with Outlook).

What would make a google calendar "wipe"? Especially since the family member didn't ever directly use the calendar only synced with app. I had them add a new entry on the app and it appeared right away. So there wasn't an issue with the account. It seems  the data just went poof?

Hoping for a Hail Mary from someone who had a similar experience.

Very strange story indeed, and not something I've seen before.
Assuming this is a free account i think there's very little you can do. I would try posting directly on Google's support forum and see if someone from Google replies. But not sure they provide support for free accounts.

We never resolved this....