Hi,
Thanks for the interest in WooCommerce Tickets. We have a 30 day refund policy you can see the details here:
https://theeventscalendar.com/knowledgebase/refund-policy/
When purchasing WooCommerce tickets you do not need Pro you only need the free version of the Events Calendar, that is the base for all our plugins.
We offer 1 year license for support and updates. After that if you choose to not renew we do not offer support or updates even if WordPress would do a major update on the commercial plugins.
We still will update the free version of the Events Calendar to be compatible with WordPress, but most likely older versions of the commercial plugins will eventually not work with it.
Let me know if you have any follow up questions.
Thanks