If you receive the following error when booking in a shipment via Whistl;

Whistl error: (404) Message: You do not have this Whistl service on your account. Please contact Whistl to add this service or use another. 

It is recommended that you make sure that you are attempting to use a service that is active on your Whistl account. If you're certain that this is the case feel free to get in contact with support who will be happy to help.