Woocomerce (wordpress) snake digital product freight / download

I have a digital product store (eBooks for download), where the customer after payment receives the release to download the product, until then everything OK. Today I registered 4 products (physical) for sending by post, using PAC or SEDEX, I configured everything right, it works 100%, but there was a problem with the digital products, now the FRETE is being charged, ie it was not to collect, already the file is downloaded. How can I disable the FRETE for digital products? I already looked everything on the site and found nothing.