Sales with Zero Markup are silent. You are not notified by email nor are they listed in the
Sales Overview Spreadsheet.
Unless a customer informs the shopowner that they have received a print of an item, there is no way for the shopowner to know that a sale was made.
It is up to the shopowner what markups they desire to add to the models. One of the best way to check your markups quickly is to download the
CSV Markup Wizard
In addition, it is important to understand that Markups are not paid unless you've collected more than $30, and that they are paid only on the 15th of the month.
@SLK, your inquiry must go to Customer Service.. there's nothing a forum member can do to investigate what items have been sold from your shop. I would say that it is valid to post something in the forum if you're having email difficulties, but you really will want to sort out the the matter over email so as to not publish your sales statistics, etc.
1) make sure you're using the email address
service@shapeways.com
2) don't cc any other email addresses - and address such as
badname@shapeways.com may cause your email to be lost
3) check your spam/junk mail folder
4) upload a new model - do you get the "Your model is now ready to order" email? (this would help tell you that the emails are not getting lost)