Liz, block all numbers from Navient if you can. They have dreadful business ethic and are so unorganized they can't keep anything straight. They break laws constantly with their famous harassment, but little is done. If you eliminate them from contacting you and anyone else you have contact with, you'll hear nothing from them. If you have no business with them and they're still continuing to harass you, try threatening them with an attorney or sending them a cease and desist letter signed by an attorney. Calls from them on Sundays are not uncommon.