Sun Aug 30, 2015 2:16 pm
When I did one recently (first missing piece out of about 20 or so sets) I typed in the part number and description in the description text box. You can get the part number off the parts list in the instructions.
Since they don't have a way to contact them after submitting the form, if I were you I'd just submit another request. It took me about 3 weeks to get my part.