I went to sell my iphone, and did the reset in front of the guy. as it was my first time of doing it, I didn't know what to expect. so the phone asked to be connected to itunes or internet. both of it were unavailable, so the guy told me, no problem, as it was working normally, he would do it home... he called me 2 days later that the phone is not working, he first said it is not working when unplugged from cable, when we met, I took the car charger to see, and it was showing only the battery lightning and the apple logo, than back again. so I took it home, made the dfu recovery, and it still does the same. the guy is lying, the phone never went on, not even plugged, and I don't know what he might have done... but I'm with no phone, no money...

what can I try next?