This is a concerning issue and one that Envato doesn’t ignore. If the author fails to provide a working file, you can report them to Envato Market Help and Support . This will lead to the author’s item being investigated.
Envato cannot enforce anything on authors except for the existing policies, one of which is that a product must work as advertised, failing to do so will get the product disabled and you will get a refund.
I also agree with @UltimateKode here since there can be issues in time with products, and authors must update their products or the latter will apply.
Get in touch with Envato Support, they’ll investigate this claim and take the appropriate action.