History of the 'Special Dividend':
I believe the first mention of this was a 3 for 1 dividend with a record date of 15 June 2012 and a payment date of 17 September 2012.
Then, that was changed to a record date of 31 July 2012 with a payment date of 30 November 2012.
Then, that was changed to a 4 for 1 dividend.
Then, that was changed to a record date of 31 July 2012 with a payment date of 31 March 2013.
At the same time of the last change it was noted that the shares will require a registration statement in order to be free trading. LOL! Good luck with that.
So, trying hard to follow along with this, it seems that your broker is correct, and that this should not be a surprise.
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