I get what you mean. Sega has to do an investigation of their own, and that makes sense. That "handshake" seems to only works one way where Steam detects something fishy, and poof, there goes both your accounts. If you want them back, you have to appeal to both companies because it's not like Steam is gonna say, "Hey, this guy is alright. We unbanned him, so you should, too."
And yes, I made a mistake when I added it to my cart twice, but that money wasn't at the point where it was going to PSO2, yet. I cancelled it before it even went to my Steam Wallet. And this wasn't even a refunded transaction, btw. I backed out and deleted the extra AC before even attempting the transaction.
So if that was the reason behind this whole mess, that shouldn't have had anything to do with PSO2 in the first place. It's an unknown reason because making a simple mistake on Steam isn't against the PSO2 TOS. If I made this mistake with another game, and my account got restricted because of that instead, would I still have gotten banned on PSO2? Probably, but there's no communication about the issue, so it's all speculation.
My gripe is that I've missed out on a lot of stuff over the past 2 weeks, and it's because Steam basically said, "That's weird... Oh nevermind, I see what happened," and it's taken 2 weeks for PSO2 to say that they're probably looking into it.