I'm still not banned as of right now. But I went in and contacted Nintendo support and told them about my concerns. The Nintendo Associate on call basically told me that while it's unusual to overturn stuff like this, but since I reached out preemptively that they may not ban my account if the credit card manages to issue a chargeback if I could provide proof of purchase.
I hope the digital receipts from that shoddy ass website is good enough.
If I manage to get away with this, I'm never using that piece of shit website again. lol
they're still going to nix you for buying from a third party website