Wow, I feel like it's kind of unreal that, in this day and age, a website as big as Webtoons wouldn't have a recourse to change your email address. I mean, that's such a basic function, of * course * it's entirely possible that your email address could be compromised somehow (or have an unusual situation like yours), and it's really disturbing to think it's that easy to lose access to all you've built up. And to not even be able to contact a help desk of some sort and get it manually changed that way--just unbelievable.
I'd also say 110 subs isn't bad at all! Especially since not everyone who reads actually subs to a comic, meaning usually the actual readership is bigger than the sub count, even if it's mostly a silent readership. The most you can probably do is just try to get the word out to people however you can, the social media people have suggested would be good, or if the original version of the comic still exists (is it still up and you're just locked out of it? Or did it disappear completely?), you can also try leaving comments in the comments sections explaining what's going on, you might be able to catch a few people that way.
Anyway, so sorry this happened, that would definitely make me want to throw something against the wall. (My series got kicked off of Webtoon after a week for 'copyright infringement' for posting a fancomic, and when I asked for more details I never heard back, so that's my story, lol. But yeah, looking back I think maybe it was just as well lol, the backend stuff for comic creators seems like it has a lot of issues on Webtoon.) Hope you get your audience back, and some more besides!