Do you have a churn policy? Is it "Good riddance"? Or as Mr. Wonderful on Shark Tank would say "You are dead to me"?
It's easy to give up on people who have given up on you. Without an understanding of why they rejected you, it is difficult to improve. "Complaints" are the most valuable type of feedback but when they "walk away" or "unsubscribe", guessing is all you have.