I  purchased  a  Transcend  microSDXC  Card  with  a  lifetime  warranty  in  January.  A  month  later,  the  card  is  dead!  It's  impossible  to  write  data  onto  it,  and  it  cannot  be  reformatted.  It  isn't  locked,  by  the  way.  I've  contacted  the  company  in  Japan,  and  one  week  on,  nothing  has  been  done.  If  a  company's  customer  service  is  this  inefficient  in  replacing  products  with  such  a  short  lifespan,  how  good  is  the  product  itself?  Caveat  emptor!
