UPDATE: HERE'S A GUIDE FOR HOW TO USE gofccyourself.com to leave comments like John Oliver asked us to. I didn't know what to do, googled, and found this link: https://venturebeat.com/2017/05/08/how-to-protest-the-fccs-plan-to-dismantle-net-neutrality/
Also: https://faxzero.com allows you to send faxes, and according to the FCC's contact page, their Toll-Free Fax Number is 1-866-418-0232