Bummer. Gets irritating patiently waiting on a luxury item that is bought & paid for.. especially when you've already coughed up a decent amount for shipping.
I think 3 weeks is ample "understanding" time given for his move. Due to it being a luxury item I get that the speakers aren't a life or death matter but the part of your story that sticks out is the excuse or reason for the delay. Can't find a legitimate shipping/freight company? Well that is just insulting.
Like others have mentioned I would take the timetable approach. Giving them X amount of days to ship or full refund please. Worst case scenario is you could probably set up the shipping yourself..& maybe ask for a minor discount for your time & aggravation. Let them know the words of West Coast legend Big Worm..& that playing with my money is like playing with my emotions.