Just to confirm, was this the issue where it wouldn’t update on the Google Calendar when looking on your phone? Does the sync work when logging into Google Calendar on your PC? Do any error messages appear?
When the Google Calendar sync window pops up, there is a small blue link in the bottom left corner that says view log. Can you copy/paste the log here or email it to email@example.com
We’ll then be able to look into the issue in more detail – many thanks!