Hi Black94cobra,
Sorry for the inconvenience caused by the issue. Have you try to access shared calendars via the App? The App is designed for iOS devices, specifically iPhone and iPad. It is available only for the customers using the latest release Office 365.
For more detailed information about installation/setup and requirements, please refer to the articles:
1. OWA for iPhone and OWA for iPad
2. OWA for iPhone
Thanks for your understanding.
Best regards,
Shyamal