@ero77,
If you are not handling child theme properly and made direct code customization on parent theme then yes all your customized code will be lost. This is not only related to our theme but also all WordPress theme available on wordpressdotorg. If you have any support related questions then feel free submit your topic at https://themefreesia.com/support-forum and its totally free. We are not available here always. We reply to our clients within 12 hours. You can visit to our support forum and i don’t think no one is happy with our support forum.
So please can you post your topic at https://themefreesia.com/support-forum and ask the solution there. Our Team will catch you there.
Best Regards
Daniel!