I am so frustrated with this order. I did not know what size to order. I received the mask and tried to wear for one night but it would not stay on. I emailed questioning what to do. I have had a series of emails but nothing has been done yet. I was last told I would have a store credit through the last email on July 11th. I have tried to reorder in the size Medium for a couple of days now, but a credit does not appear. These masks are on sale now and I would like to get the mask as soon as possible. I'm afraid if I go ahead and order and pay for it, then I should still have a credit, and frankly, at this point, I'm not sure I will order from you again to use a credit since this one hasn't gone so well.