i just bought a 16 gb sony micro sd card and i have problems

[AC Question]

I reseted my phone and everything nothing worked I checked it says I have 12 GB left nothing works

 

[B. Diddy]

Welcome to Android Central! Which phone? Go to Settings>Storage. Does it show the SD card there? Does your computer read it? If not, it might be a defective or counterfeit card. Where did you get it?