The Contact Information includelet is what's showing the map. This includelet will show the address and contact details from the Website Details page in the site settings, though it can be configured to show different details.

(And so, if you've changed the website details and it hasn't changed, it must be configured to show other details - so go to the Layout tab for the homepage, and check what's configured in the includelet's settings).

There's more about the Contact Information Includelet here.

Thanks

Joe