It's GDFS. Restore it back to the old GDFS. But since you used your friend's GDFS and you don't have a backup GDFS, you basically killed your sister's friend's phone. Nuff said.

Oh, and Rogers won't accept it either cus you're not using their firmware. They'll just say like "oh it's your fault for doing this, for doing that, etc. etc." Only hope is to send it back to Sony Ericsson now.