I've been doing a lot of searching and finally found Square-Enix's Japanese Support Center E-Mail after an hour of searching. I just sent them a request to unlink my ID, but if they refuse, I'll be forced to continue paying high fees each month. That's not even the worst case scenario- I feel kind of at risk by contacting them. Hopefully there are no more issues that spring up. All I want to do is pay a normal price each month instead of $18 for a single character. Depending on what they say, I'll likely give one more update.

I don't mean to fill the thread up with a bunch of unrelated posts or anything, I just want to make sure that any others going through my situation could use this information for their own assistance.