I need to admit that before reading anything, I played with settings and changed my plan for pay per traffic to subscription. Unfortunately, the information was not clearly visible for me to notice that I cannot change anything for one month. Is there a possiblity to take that back?
No problem. :-) I'd changed your data plan to PPT (Pay Per Traffic) and reset your changeable date too. If you'd like to change it back I think you can do again.