Good advise to go with the cerdit card company and file a dispute. I am not sure if this helps but read through this, it has helped me before "remind" folks if they wrnty. something, they need to stand behind the product. I do not know what your speciffic situation is, with how they described the mags up front, but if they were supposed to work....this may help. Good luck.
Magnuson–Moss Warranty Act (Federal Act)
Magnuson–Moss Warranty Act (Federal Act)