I had this exact thing happen to two different orders. In my case is was my credit card company that lock my card because they thought it could have been fraud. (MS ran multiple charges for each of my orders, so after the first 4 charges they locked the account, and the big charges for the Surface Books were declined.) I called the bank and got that cleared up and then called Microsoft who said that everything was OK, and that they would try again. About half an hour later I got the cancellation notice. I called again and they said there was nothing they could do, so I had them refund the Surface Book Complete charge. I asked them to check my second order and the second he pulled up the order it cancelled it as well.
I went ahead and placed the orders again, since I want the referral cash-back as well as the 10% education discount which they wouldn't have given me over the phone if they re-ordered it. (I was told 6-7 weeks when I placed the order, so they were shipping much sooner than I planned anyhow. And hopefully by the time I get it all of the initial bugs will be worked out.)