iPhone 5 stuck in recovery mode after repair.

My iphone 5's power button stopped working so I took it to a technician as Iphone has no warranty in Pakistan. He replaced the button and restarted the phone, it started but did not pick any signal. He restored its network settings and phone started to work. But the button he replaced was no good and I asked him to replace it again. He did, but the phone did not pickup signals this time even after restoring to network settings. Everything else i.e. wifi, bluetooth was working just fine but the signals bars showed 'Searching' even when the sim was removed. So, he tried to restore by connecting it to itunes but failed. So, he tried to update the phone as it was previously at 6.1.2. But in trying to do so, iphone got stuck in recovery mode with the itunes error (-1). Please help me :-(