Hey there NoMan99,
Thank you for using the Support Communities.
I was researching the issue you are describing and I found a couple of articles that may help you.
iCloud: Troubleshooting iCloud Calendar
iCloud: Advanced Calendar and iCal troubleshooting
A Lot of good information, and certainly worth hanging onto. Unfortunately, does not solve my problem.
Good 2-way communication on calendar and contacts between iCloud with iMac and iPad. Thus those devices and iCloud properly configured.
Good 2-way communication between iPhone and iCloud. Thus those devices appear properly configured. iCloud calendar (and iMac & iPad through iCloud) communicate TO iPhone -- but it sometimes takes more that a day for iPhone to get the entry. An entry in iPhone NEVER goes to any other iDevice.
In that case thank you for using the Apple Support Community. Due to the nature of your question you may find more information by using another one of Apple's support resources - https://expresslane.apple.com/GetproductgroupList.action.
My iPhone4S is not syncing its Calendar from my iMac. I have read ALL the posts and all are way too complicated. Strangely, four weeks ago, I had the same problem. I took phone and Mac to the local Apple Genius Bar. I have four email accounts. Two Yahoo, Gmail and iCloud. The techincian went to settings/mail and did something to uncheck one or two of the email accounts and EVERYTHING came back. Unfortunately, I do not recall how he did it. Any answers? By the way, two other technicians on the 800# did not have a clue.