We have had an ongoing problem with our website calendar and all of the changes not syncing quickly enough for our liking or showing double entries etc.
We have redone our calendar from top to bottom and it seems to have fixed the problem.

We have had a few issues with people adding our calendar entries to their own calendars as well and I have figured out why this is happening as well.
The problem happens when you are accessing our site through something other than a web browser eg) Through a link on Facebook or Twitter etc.

Here is a step by step instruction:
1) Open a web browser like Safari, Chrome, Firefox etc.
2) Come to our websites Calendar page
3) Scroll to the bottom and select the ‘Add our calendar to your own button’
4) It will take you to another screen with 6 choices, select the appropriate one and your device will pop up a window with a list of our calendar entries.
5) Select ‘add’ and the entries will be added to your calendar.
6) Repeat for other appropriate choices if desired.

To get rid of the old calendar entries on your device go to Settings…Calendars and under Accounts there should be a Subscribed Calendar labelled ‘All in one…’, delete that and all of the old entries will be removed.