This is actually something we see more than you would think.
An organization provides a physical address, either for mailing or for visits or for both, on their Contact page, and also on their site footer.
BUT the addresses are different – and clearly, one is wrong. Which do you suspect is right?
If it is a content management system web site – WordPress, Joomla, Drupal, etc., we would suspect the Contact page is right. An organization’s content manager is more likely to know how to change that rather than a footer template. And it is more likely to come to mind to a content manager – there is an actual page to see in the content editor software.
If you need the address, and there are two listed, do them a favor – call their office and ask, and explain what the source of your confusion is. They will probably appreciate the information.