What does the Bible say about paying a bill that you should not have been charged and it won’t go away?
As believers we’re admonished to pay everything we owe in a timely manner; taxes to whom taxes are owed, revenue to whom revenue is owed, respect to whom respect is owed, honor to whom honor is owed (Romans 13:7). But I don’t know of any general Biblical requirement to pay an unjust bill. What the Bible does say is if a disagreement involves a fellow Christian, and if it comes to a lawsuit, it would be better to be cheated than to take a brother or sister to court (1 Cor. 6:7).