I checked out that site and laughed my ass off. They claim they offer a direct debit solution for the Netherlands as well, but it would be a miracle to get a sale through that system.
The translation into Dutch (actually half of what I read was German!) is terrible, and in order to pay you need to know your bank's SWIFT code. If 1% of the people know that code, I would be surprised.
Maybe their German system works well, but you can safely forget direct debit from the Netherlands. (For anyone who thinks they will unlock the Dutch market with that service ;-)
Greetings,
Art