My iPhone 5s was stolen. I have it locked down with passcode and fingerprint. The thieves tried to use it once about 40 minutes after they stole it. but have not turned it on since. I want to wipe the device but, according to Apple's site, I can't track it and it will then be able to be activated by anyone. I certainly don't want either of that. Please see "4" at http://support.apple.com/kb/HT5668 Is it gone forever and totally able to be activated if I do wipe it? Is there a site I can put my S/N and/or IMEI so that it is blacklisted from being activated?