The decision to allow the trade was the brokers. The brokers could have refused the trade. Instead the broker took my money and promised me shares.
And the decision not to break the trade within T+3 was also the brokers. The broker had an opportunity to break the trade,and return my money. Instead the broker kept my money.
Nor did my broker tell me anything about the DTCC freeze.
It was certainly being discussed here.
Do you have any Proof the freeze was discussed and what it meant? I don't recall anything of the sort being stated as a fait acccompli (the freeze of Aug 11).