mobile data galaxy s5

A

AC Question

Hello

So I bought this phone last month, in August. Everything was fine until i got a notification that i had used all of my mobile data... So i waited and every 12th of a month, my data resets itself. But right know when i don't have wifi, i can't use Twitter, snapchat... My mobile data is on but it doesn't work? Does anyone know the problem? Thanks!

sorry if my english isn't that good, i'm dutch...