Fontio has helped our store to beautify the fonts. However, sometimes the font do not work. There's currently no way to coyp and paste your custom css lines as a backup. We tried reaching out to support and are still waiting (for a few days now) for them to roll back the fonts. It'd be better if they could respond quicker.
We're really sorry that this happened to you guys. Unfortunately you got caught in a miscommunication between us and the previous owners of Fontio and we're only just seeing this review 2 weeks on.
In those weeks we have hired new developers and requested collaborator access on your store to try to solve the conflict which led to your issue.
We appreciate you sticking with us!