Hello! Domains like "helio.st" are not available in our free domains. I've guessed that you meant "familybudget.helioho.st" and added that one.
Please note that it may take up to 2 hours for the domain change to take effect.
If after a full 2 hours it doesn't work on your side, please make sure you clear your web browser cache: https://wiki.helionet.org/Clear_Your_Cache
I also removed the familiybudget and api.familiybudget subdomains as requested. Please note there is a risk of data loss when domains are removed, since the folder for the domain inside Plesk will be deleted.
I made a full account backup for you before I removed the subdomains, in case you need any of the old files. You can download the backup here: https://heliohost.org/backup
If you're not sure how to extract the backup files, please follow our how-to guide here: https://wiki.helionet.org/Account_Backups