Used All Up all my Data, Now can not make calls
For some odd reason, all of my data has been used up for the month. I think this was due to a samsung lollipop update which used it all up. But now, I can no longer make calls when away from home. I can make calls via wifi. Data is still turned on. I am getting a weak signal error message when trying to call away from home. Any suggestions. I have a samsung galaxy s4.