Trial ending for premium service but would like to buy Basic service

I setup my trial for premium service but found I only need the basic service.
I don't see a way to buy that option -- can anyone help with this ?

Hi, you can change subscription level by going to the product page for the new subscription and click buy. The subscription system will pro-rate any remaining time on the old subscription and add it to the new one.

For example, basic service is accessed from this URL :
https://www.nuevasync.com/PublicSite/user/commerce/catalog.htm?product=basic