The argument that I was discussing was the one concerning the atonement. Some believe Jesus paid for everyone's sin universally. Some believe in a limited atonement.
As I know you are well aware, this is an ongoing argument on this site between those with Calvinistic and Armenian bents. I'm neither. My argument has to do with God's claim to being just.
Some believe that Jesus has indeed paid the sin debt for every person...past, present, and future. If this is the case, there are people in hell whose sins have been paid for. Not only are they paid for, but God has accepted Jesus blood as payment for their sins. Thus, there are people in hell whose sins are paid for and whom God accepted payment for their sins and still required another payment.
God is sovereign and can do as He pleases. But He cannot require a payment, accept a payment, and require a second payment and still be just.
If one doesn't believe God is just there is no quandary. But if God is just, how can He require payment, accept payment, and still require more?