debt? sounds like you want retribution.
As long as your mindset is on punishment, rather then to fix (if possible) what drove the person to such undesired behaviour, it's going to be hard to forgive. You want to lock up people because you have to, either as a WORKING deterrent, or to keep people outside jail safe.
No, I don't want retribution. I've slowly come to the belief that prison should be to keep people who cannot function in society separated from society until they can function in society. It's punishment enough for such separation, I don't agree with "hard" time.
And what's so wrong with retribution? If you cause suffering to another during their short and precious time on this world, why should you not be made to suffer as well?
This desire for retribution is a central part of the human psyche. As we have done for our other wild drives, we have tamed it with process and institutions, but we should not deny our moral intuitions. If you reject the legitimacy of moral intuition, then you'd have a hard time justifying why blackmail should be illegal, for example.
And in some cases the debt is not repayable.