What you were sent is an admission someone in Scottrade screwed up and now they seem to be doing damage control.
At no time does DTC or their parent company the DTCC ever hold anyones stock from being transferred, or in this case, since there was no SEC or Court Ordered trading halt in place, being sold on the open market.
A DTC Global Lock as I have written many times, is not a freeze but a chill and in no way gives anyone the right to do what you have written (and I do believe this to be genuine).
Scottrade and no other brokerages can set themselves up higher than the SEC and the US Government to seize anyones holdings for themselves, for any reason short of something being done illegally by a client and even then by a legal order.