An answer to your ongoing question "is God just if he sends people to hell....", yet to be answered satisfactorily, has just occurred to me while I was considering that we all are going to get justice. or be justified. But you're question implied that God doesn't accept the (Jesus') payment for the sins of those in hell, or rather that it doesn't apply to them (with offered reasoning that He must not have died for them). Because there is no forgiveness of sin without the shedding of blood, for the wages of sin is death, and so death is the (only) acceptable payment for sin. And assuming that we agree on that, that leaves the question whether God is just if, given that it was possible that God would accept a double payment? And if not, who would receive the refund on that?
And yes, this question does exclude the possibility that man's sins are so grievous that he has to spend an eternity "paying" and still can never fulfill the debt, but rather assumes that it is possible that man pays for his own sin, by death.