Yay for Patternworks! I e-mailed them about the skeins I want to return and they said it would still be possible - although it would be best to wait until they get back up and running at their new address.

BTW, the company they are now affiliated with is Keepsake Quilting. I really shouldn't have worried about whether or not I could return the unused skeins...have bought from Keepsake in the past and have been very happy. And will buy from them again in the future.