Abstract: In general, a call rating and debiting system provides a way of rating and debiting complex debit card calls. The system estimates the time when a subscriber's balance will expire by using total charges for all calls for a given time period. Estimation is performed by accounting for time already paid for, reserving a minimum continuation time for adding a new call, reserving time for all calls up to a latest paid for time, estimating remaining time before a subscriber's balance reaches zero, based upon a remaining balance achieved after the system accounts for time already paid for, reserving a minimum continuation time for adding a new call and reserving time for all calls up to the latest paid for time, and setting a time limit for all calls in accordance with any portion of the aforementioned. An alternative embodiment of the system allows a subscriber's account balance to be automatically increased after the balance decreases past a predefined minimum.