Doubts: 4 layer PCB appear to be 2 layer?

Hello Everyone,

I uploaded a 4-layer pcb (1-sigal, 2-VCC 3-GND 4-signal) to BatchPCB and passed the DRC. However, I realize in the page where it shows the information on my board, there is an item says “Layers: 2” while I made four layer for my PCB in Eagle CAD tool. Did I do something wrong in my design?

Thank you guys!