I checked some of your closed listings and didn't see anything in the checkout messages about 23 inch wheels. What are the ID numbers where your customers were getting this? Also was it the WBN email and not the checkout, or the checkout as well?
I checked the listing's checkout and cannot see any references to 23 inch wheels. You have the carbon copy option selected -- do you have copies of the WBNs in your email account still, that went to customers that said they got the 23 inch wheels item mention?