Hi,
Sorry for the issues here. I can help out.
It should be $60.00 USD
I tested out the Upgrade System and when I click Business it gives me the correct amount.
If I click Unlimited it gives me the $661.
After logging in.
Please go back to the cart:
https://theeventscalendar.com/cart/
Remove the Unlimited Upgrade if still there or another thing else in the cart.
Once empty then go to the License Page:
https://theeventscalendar.com/license-keys/
And click Business next to the license you would like to upgrade.
That should now correctly add it to the cart.
Let me know how that works out.
Thanks