So we'd say that When I sin, I , in principle, owe a debt to God. But we say "in principle" because it's paid. But I may also owe a debt to someone else, and THAT debt is not paid by the atonement wrought in Christ.
Oh wait! In a way it is. If I forgive the debt, then I am paid by Christ. Isn't that somehow right?
It's interesting, and I'm wanting to pick my way carefully, because of ψ 51 v. 6 "against you only have I sinned .." And that seems really true at a deep level. All sins are against God and all debts are somehow owed to Him. And thanks be to God who has in Christ squared the account.
I think where my mind wonders next is to wonder, as I have been doing for about 11 months or so, if accounting is an adequate analogy for justice.
That is why I used the word damage, not sin, for the other people whom you have affected. We still need to pay damages if we have done someone wrong, but all our sins have been forgiven by God.
For example... take the sin of drunkenness. You will pay for your excess, maybe with a hangover, sick stomache, an angery wife, etc, but the sin against God (excessive drinking) is forgiven.