Won't accept MicroSD card greater than 16 GB?

So I tried putting in my first sandisk 32gb, and it failed, kept saying bad file system or write protected.

Figured it was the card. I had also bought a 16gb for my phone, galaxy s4, so I put this in the tab, and it worked fine.

Then I found a deal on kijiji for 64gb sdxc 80mb xfer rate, for $45, perfect for the tab!

installed it, and there were no errors like the 32gb, but I can't use it. Can't put any files on it.

But the 64gb card DOES work in the phone. So it's not the card.

It's like my tablet is just not accepting cards above 16gb.......

I just bought the tablet on boxing day, with an open box sale + a boxing day sale.