My first guess would be that somebody is using your wireless. If you're concerned that it might be unsecured or somebody has your password visit http://www.cox.com/residential/support/internet/article.cox?articleId=3c29e430-6e68-11e4-d31e-000000000000 for more information on how to secure your wifi and/or change the password.
My first thought is your neighbor is connected to your network. Is you network secure? Are you using WPA2-PSK encryption? At any time in the past, did you give your neighbor your network key (password). If so, their device can remember the password and reconnect to your network by accident. Once on your network, anyone can access a network connected printer. I would: (1) make sure your network is secure, (2) implement WPA2-PSK if not already and (3) change your network password ASAP if your security is OK.