I dont doubt you given the negative feedback on his profile, but imo there isnt enough proof here, you should post screens proving those keys were redeemed as well as your conversation with hikah where they tried to "play it off."
OP is probably right, those keys are most likely poisoned like VOD said and warned everyone, if the buyer accepted to take the risk its his fault honestly.
I didn't know, at the time, that people could delete any negative replies/feedback on their threads, hence, after he overwhelmed me with shit for days, I fell in his trap.
It's hard to take Vod's feedback to mind when he's giving the same feedback to every
thief/MSDN seller out there when there in fact are legitimate ones, although very few.
If I had known about the ability to moderate your own thread, which I do now, I doubt I would fall in the same trap again.