How to get my internet to work on my straight talk Galaxy s5 Mini

[hancherella]

I bought a Galaxy s5 mini that was unlocked and then later purchased an at&t straight talk sim card. Now I can't seem to get my internet to work. I've tried a million different "APN" settings and tried calling straight talk support twice and both times they told me to give it 24 hours and call back. Starting to get real disappointed and just want to get on facebook. Seriously please help me:-\