Hi! From what I can see, Nokia C7 runs Symbian and Firefox has been never supported in that Operative System. Perhaps you have been running an app that allows you to use Firefox Sync with your device. Unfortunately I don't know what app you were using so I can really help you. If you could be more specific we can try. That said, a lot of improvements have been added to the Firefox Sync system and if the app that you were using hasn't been updated you may be unable to use it anymore.