You can remove the duplicate subscribed calendars by opening your device’s Settings app, then deleting all but one of the Roster Buster entries under the “Mail, Contacts, Calendars” tab.
category: Export calendar
title: iOS calendar
This seems like a quite complex, because we’re now also interfering with the standard process in which Apple creates these subscribed calendars. I hope I can support you on this one.
1. Please start by removing your subscribed calendars from the Settings >> Mail, Contacts, Calendars >> Subscribed Calendars menu.
2. Open the RosterBuster app and go to More >> Export to WebCal and click on the subscribed link. A new subscription should be opened on this device.
3. Please also try to do the same on your other device you want to sync with this WebCal.
There is only one unique link, you can register on multiple devices. The link refers to a collection of events on our servers. The WebCal calendar updates itself automatically.