Unproductive consumption of unwarranted enrichment excludes the work to refund the benefit — unless the enriched 1 should have foreseen that he would gotta donate

And now something from a somewhat different barrel, or a fewer sentences, that an unwarranted 1 doesn't gotta quit the benefit if he has given it up and is no longer enriched — but the expiry of the work to return unwarranted enrichment only happens on condition that...