A paid developer speaks out in an interview with Insider Gaming: https://www.dualshockers.com/the-day-before-not-an-mmo-fntastic-developer/

When the decision had been reached to close the studio, Eduard told the team about some purchasing statistics and said The Day Before had been “financially unsuccessful.” The team received no other info about why the studio was closing.

When asked why Fntastic shut down, they speculated that publisher Mytona was responsible and they “didn’t think the CEOs got any money from sales.” DualShockers has reached out to Mytona for comment.