If you buy something with promo credit and then cancel the order, is that correct that you lose your promo credit?
Nope, you get the promo credit back on your account. Tested and verified.
Funny enough, I did end up cancelling my order and I had to contact customer service because I didn't get it back. It was with a little resistance though. The rep said that promo credit is like using a coupon at the store. You just get back what you paid when you make a return. She did eventually add it back saying she would make an exception.