I think there's a bit of arrogance on both sides. Just shipping some random guy $5k worth of btc is...risky, to say the least. I also don't understand this whole "Bulgarian" thing. And "partner". That just seems shady to me and a cop out to try and pass blame elsewhere. However, he did agree to a payment plan. Although I'm sure he has some btc stashed away and should at least refund you what he can.
If he claims to have done "200k in transactions this month alone" he should have no problem paying the guy.
Honestly segvec sounds like one of those self righteous guys and is only doing this out of spite to prove a point because he's a fucking asshole.
Good luck making trades and don't worry segvec -- your name will be spread around the internet and negative feedback will be given where needed. You will also be doxxed