Good evening Torbjörn and welcome to the Events Calendar Support forum!
Thank you for reaching out to us.
We are sorry to hear about the tickets disappearing on you while using WPML.
I would love to help you with this topic.
You are right. At the present time, we do not offer WPML support for tickets.
You can see that here: https://theeventscalendar.com/knowledgebase/wpml-support/
The good news is that work to provide such compatibility as started.
Unfortunately, I cannot commit to a release date at this point. But stay tuned!
The good news is you are fully entitled to a refund if you want one since you are within 30 days of your purchase. To obtain the refund, you just need to follow the procedure described here.
I wish I had a better answer for you, but for now it’s the best one I have.
Have a great day!
Geoff B.