Try contacting the owner and let him know your complaint. As a small business owner I would love to have customers come to me with this. This kind of sales technique is not in anyone's best interest and certainly not how I would want to have my name and store represented. Correcting this situation would be a kindness both the store owner and the sales clerk.
When in doubt kill them with kindness.
If that doesn't work, in the south we can fall back on the old saying: "Well, bless his heart!"