403 no permission, help??

Okay, so I recently moved to wordpress.com and moved my site with it, im using bluehost to host my wordpress site.
when people try to download their purchased product on my site, it says:

“403 permission denied, You do not have permission for this request /wp-content/uploads/woocommerce_uploads/2015/05/drawing_straight_line.zip”

iv tried to fix this for a few days now, and im losing customers, some becoming quite angry at me.
please any help is needed.