The NCOALink database is for moves only; it cannot correct addresses that are not complete (i.e. missing suite number) or that are invalid. Undeliverable pieces are likely if people don’t register their move, or if the database hasn’t been updated since their move. The database is updated every 90 days or earlier. It can also occur if an address is just invalid, as well as a variety of other reasons. When a piece is returned, we recommend you use the information contained on the returned piece to determine the cause and take corrective action by either removing them from future mailings or attempting contact by phone to get the correct address.