Gotta have setting to limit the amount of times users can send such apeal.
A link to "Create New Ticket "in the page that the suspended users see may be enough.
I have this link in the bottom of all the pages.
For the tickets I use this plugin that works very well:
https://developers.oxwall.com/store/item/1518
As i said with several admins or moderators then you can assign someone to do this for you as part of their role, but it will be a headache for one admin.
Also consider that if you let people appeal your decision then you better have a set of written appeal rules drafted because if you approve one persons appeal and not another you better have a really good reason and it needs to be in writing to cover your butt.
One of the first things a user will claim is "well you let them do it"...