I recently bought a slightly used i760 on ebaY. Tried to do the 6.1 upgrade before activation and couldn't through my USB ports so I called Samsung tech support. They sent me a UPS shipping label, re-flashed the phone with the latest software available, and sent it back, all at no charge. I then proceeded to load my software and have the phone activated.

The whole process took 12 days from dropping it off at a UPS Store until I got it back.