Did it ever come out anywhere just how Lobo was barred from either place?
Basically he died and went to Hell and caused so much chaos that they booted him out, because he was still dead he went to Heaven and did pretty much the same leading to god issuing what I call the Memo of Immortality to keep him out of both places. And yes it is an actual memo from god
It's described that God won't take him, and satan is afraid of him... basically he dies and gets sent back or reincarnated.
@ArturoCalaKayVee Lobo should join the Justice League.
Also, during the Imperiex wars, he was on Young Justice...