I've 'exchanged' a shirt before and the service was excellent. I emailed their customer service and they were very accommodating. I placed a new order for the correct size (it was my mistake) and paid for it. At the same time I sent back the incorrect size. My new shirt arrived quickly and when they received the shirt I was returning, they reimbursed shirt and my shipping costs. Hope you get the same experience.
6/26/15 at 1:47pm