Hi @spets24,
It’s been a while since you posted this so you may have found a solution. If not, try going to Analytics > Settings in your dashboard. Then scroll down to the “Import Historical Data” section. You can delete the existing data and then import it again. That would be the first thing to try and find the missing customers in WooCommerce > Customers.
If you’re saying that they are missing in the Users section of the dashboard, that likely means they weren’t transferred successfully. If you still have access to the old site, you may be able to export them and import them into the new site using something like https://wordpress.org/plugins/users-customers-import-export-for-wp-woocommerce/
Let us know if you have any questions.
Since it’s been a while since we last heard back from you, I’m going to mark this thread resolved.
Hopefully, you were able to find a solution to your problem! If you have further questions, please feel free to open a new topic.
Cheers! 🙂