pitr-lokam vrajanti te
prajam anu prajayante
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Such materialistic persons are allowed to go to the planet called Pitrloka by the southern course of the sun, but they again come back to this planet and take birth in their own families, beginning again the same fruitive activities from birth to the end of life.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
In Bhagavad-gita, Ninth Chapter, verse 21, it is stated that such persons are elevated to the higher planetary systems. As soon as their lifetimes of fruitive activity are finished, they return to this planet, and thus they go up and come down. Those who are elevated to the higher planets again come back into the same family for which they had too much attachment; they are born, and the fruitive activities continue again until the end of life. There are different prescribed rituals from birth until the end of life, and they are very much attached to such activities.