Does the field actually have any value?
<?php get_template_part( ‘data/index’, ‘acf’ ); ?> Is it correct?
No, I mean whether the field has any content (or rather, is anything selected, if it’s a select field) in the admin area where this field appears? You are giving very little context here.
That it returns “false” sounds like nothing is selected or it has no value assigned. Could you please share the field settings and what it looks like in the admin screen?