Stupid ban reason

Not at this point. You can only submit a review while the suspension is active

nope, as there is no way to contact them, they are a seperate department that have no external contact, even support cannot do anything as its above their remit and they also cannot contact that department.

I think it's too late because It won't let me submit a ban appeal so can I not do anything

Sorry to hear it. Unfortunately no one here can help with enforcement issues. The PET are in sole charge of enforcements and can only be reached via the case review at http://enforcement.xbox.com/

you would need to go to the enforcement site to submit a review but you have left it a bit late and that might not be available now, nothing else you can do as the review option IS the only way to contact them.