Hi! Please note we don’t provide support over weekends, hence the delay.
I logged in (thanks for the credentials) and entered the license key we have on record for you, which seemed to stick, and went on to update Events Calendar PRO to 3.4. Everything seemed to work smoothly – so I’m not sure why you were hitting problems, but can only guess the key was incorrect (you can review the key I entered and see if that matches what you were using).
At any rate, I hope that helps and let us know if there are any other problems with this.