wow, that is strange. All the ones I've seen are square too. I tried to google that and couldn't find anything. Try calling Hechinger at 888-801-2559 and see if they can help. Can you get your money back?
thanks for the reply!
yeah, I spent lots of time googling with no luck. Thought it might be an OEM hitch. Can't really take it back since I grabbed it while visiting my brother and he's 800 miles away.