Debts
Who owes whom, deadlines, partial repayments and write-offs — attached to people. Nothing lost track of.
A debt here is a person, an amount, a deadline and every repayment separately. Half came back — you can see what is left, and when the rest arrived.
Debts lent and debts taken are counted both ways, and a settled debt does not vanish: its history stays exactly when it is needed.