"The developer" is actually Mark Karpeles (MagicalTux), so I'm fairly confident that this will be resolved.
Do you think that when I wrote to Tibanne Co., Ltd. (throught their contact form
https://www.tibanne.com/contact.html or maybe
contact@tibanne.com), it will escalate to him?
By the sounds of it, your issue already has been escalated to him. He's just really busy, so it might take a few days to get to you.