I ordered some Fenton headers from them on sale, and they were back-ordered. I don't remember if I ever got an estimate on when they'd show up, but in the mean time I had found some on eBay, and got them. I tried contacting Brothers by email to cancel my order, which apparently worked, but I never got any confirmation of it. I ended up calling to cancel my order, not knowing they'd already done it, and the guy and I were both trying to figure out what was going on, since I was trying to cancel an order that he wasn't finding in his system.
Anyway, turned out fine in the end, but if you end up canceling your order, I recommend doing it by phone first since it's not likely they'll reply to an email.
