Hi @Justin - if it's just a sizing issue and doesn't fit at all then the first order of business is to contact support@nfcring.com and let them know what's happened and what you need.
To help them out a little make sure you use the email that you use for kickstarter, state clearly in the subject field something along the lines of 'Kickstarter backer, ring size return request' just so they immediately know whats going on before even opening the email.
Inside the email if you could state your name, kickstarter pledge, type and size of ring received and what you're hoping to exchange for then that'd be great.
They may ask for some more info but as long as you help them out straight away with the basics then that should make the process a lot easier for everyone.
In the meantime, depending on what you want to do, whether it's return and exchange or purchasing a second one with discount you may want to keep the ring inside it's velvet pouch so it's still in saleable condition for if you do return it.
But most importantly make contact first, don't just send the ring back!