i think customer support missed that one.
adobe serial numbers are product specific. you can't activate a trial of one product to a full version of another product.
you need design standard cs6. here it is: http://www.adobe.com/cfusion/tdrc/index.cfm?product=design_standard
if you have a download assistant issue and need to download directly, follow all 7 steps and dl from here: http://prodesigntools.com/adobe-cs6-direct-download-links.html