People have mail-ordered many, many kinds of illegal drugs. The thing is, they all get it from actual dealers who somehow mail it without it getting confiscated (must be rather tough). There's no "vendors." Benzoylmethylecgonine is cocaine, if there's some called cbenzoylmethylecgonine, then maybe it's a different kind that's not scheduled (and not even recorded anywhere on net). But I think the c was just a typo, right?