Hey Karolina,
I’m sorry you’ve run into these issues on your site!
This unfortunately seems to be a theme issue, but before we get to that, can you first clarify the following details?
1. What version of The Events Calendar is active on your site?
2. What version of Events Calendar Pro is active on your site?
3. What version of WordPress are you running?
I will try to recreate this problem based on that information – if I cannot then I will recommend these steps to you: https://theeventscalendar.com/knowledgebase/testing-for-conflicts/.
Thank you!
George