To pay back a debt I can either, donate or I can volunteer. But I realize now that volunteering, although it pays the debt at a faster rate, also endangers my school work. But what is more important paying back the debt faster or the work?
put your priorities in order
what is your primary duty in your current state in life?
first and foremost is always the duty to God, prayer, worship obedience etc.
Then is duty to your family according to your state in life
then to your current “job”–student, housewife, fireman, whatever
then to your immediate neighbors and those with whom you are in contact regularly
then to the wider community.
If volunteering endangers your school work, figure out why, figure out how you can better organize your time to do both properly, or cut back on the volunteer hours and concentrate on school. For most people this would not be an either/or issue, it would be a call to better time management.