I think it is related to the user account you need to have with them when working with the plugin. An order will be automatically shipped with them .
The shipment method is there, but only if i keep shipment & billing separate, which i would like to combine. Also it shows on the billing page, not on the shipment page, where it should calculate the costs. Besides that it shows, it is not working. When filling in an address the prices and shipping options should appear.
If you want to check, I can give you access to the back end my test site, there is no customer data there. Can I send you a private message with the login?
If my problem is too typical for normal support, I understand. I see mollie is working, which is the most important. The shipping is a nice to have for me.