Yea I spoke to his girlfriend first, and I'm too far now to go back to a previous save. I have tried taking it off and putting the amulet back on again, but he still won't talk to me. There are a couple of mammoths nearby but they're not hostile or anything.... I think this quest has just glitched.
Currently playing: Battlefield 3, Skyrim, Dark Souls, Ni No Kuni. PSN: PrincePAUL87