Hello Frantisek,
Can i ask are you using the latest version of Easydiscuss? If no, try update to latest version of Easydiscuss and see how it goes.
If Yes, Is it possible provide us with your Joomla backend and FTP access so we can help you check on this ?
Also, It looks like your account isn't tied up with any subscriptions on our site. Is there any mistake on our end? Would it be possible for you to contact us at
https://crm.stackideas.com and provide us with the order reference and your username so that we can fix this up for you?