Where can I buy authentic Wayne Goss brushes for contouring?

Hello, everyone! I really want to master contouring and wanted to buy Wayne Goss Brush 13 for my contouring needs. I noticed that Beautylish has it available but for some reason, they don't have Puerto Rico as a shipping option on their international (or regular) websites. I'd like to buy this brush from a trustworthy place (I'm scared of getting a knock off), any suggestions?

Also, I've read that for contouring you should have 2 brushes (one for highlighting and one for shadowing); what would Brush 13 work best for? And which of his other brushes would you suggest to completely fulfill my contouring needs? If you don't know where to buy Wayne Goss brushes other than Beautylish, which high quality brushes would you suggest for contouring? Thanks in advance for any help!