I have had nothing but positive experiences with Zulily. There have been a couple of orders I wasn't happy with, and they were handled very well by them.
An example-had ordered a pair of plaid clogs. They came, but each shoe had the plaid going in a different direction. I emailed them with a picture, and they wrote back that they could see the problem, and I was credited, didn't have to return the shoes (donated them) and they gave me a $10.00 credit.
I am always careful when ordering clothes to check their size chart. It is different for each brand you order. Only have gotten one thing that didn't fit as I thought it would. Gave it to my sister who loved it.