Hi, My suggestion is to call Best Buy's Geek Squad customer service and explain to them of the issue. Also, speak with the sales associate that sold you the machine. If the sales associate did not ask you what chord type you may have at your house, then I think that is where the issue resonates. If that was never brought to your attention, then you have a case for Best Buy to exchange your machine to the correct chord.
In my case, I was asked how old was our home and do you know if you have a three or four prong chord.
Good Luck!