Last resort. Get iFunBox on your PC, or if you have OpenSSH on your device and an SSH/FTP client on your PC, you can use that as well.
Navigate to the following directory
/etc/apt/sources.list.d/cydia.list
Make a copy of the cydia.list file onto your PC, then open it up with Notepad. It might not be readable by Notepad by default, if so, just right click, and click Open With.... and choose Notepad anyways. Or just any word processor. Notepad is simple and to the point, so I prefer that personally. But anyways, once it's open, delete any and all sources that's NOT the original sources. Or you can just clean out the entire list except for the Saurik one, and re-add them all on your device manually.
Once Cydia.list is cleared up, put it back in the same directory you got it from, which is /etc/apt/sources.list.d/, replacing the old/unchanged one. You might have to respring or reboot your device. Open up Cydia again, and re-add the sources that you've deleted.