There is no karmic debt that must be repaid. As a soul you are not obligated to do anything. However, you did make a decision before you were born as to certain things you would like to experience this life. The desire to create these experiences hinge on previous choices you made in past lives. Karma is more of an innate desire to achieve greater things based on the past. What you are now experiencing is a measure of that past.
Many imagine that the process of life is about working off past debts and doing your best not to incur new ones. The cycle of life is more of a process of the soul experiencing different feelings for the sole purpose of gaining wisdom. Think of the colour white that exists as a result of every other colour being present. Now think of love as the summation of all feeling. The highest love being the aggregate total of all of your emotions and feelings like happiness, joy, truth, hate, jealousy and possessiveness. For you to experience compassion and selflessness you need to know what it is. How do you know what compassion and selflessness is, if you have nothing to compare it with.
Experiencing the many aspects of your feelings and emotions has and will take many life times. You maybe questioning your life as to what aspect of your ‘being’ you are now experiencing. Knowing your past lives can give you an understanding as to what karmic lessons you are now working with and why. Be sincere in your motivation of everything you do, as all of what you do moulds the person you desire to be.