MB Still accumilating on no battery model, 5G Gateway when UNPLUGGED

Do not have internet on T-Mobile phone or TV, only use Gateway for I-Pad and Laptop. I ALWAYS turn off internet setting via SETTINGS on both devices when not in use. I push button to off on rear of Gateway (even though I have been told I do not need to because my model has no battery back-up) and pull PLUG out for the night, yet my USEAGE keeps showing all sorts of MBs being used during these times. Have verified am not being hacked, so what’s the deal? How can I be using MBs when Gateway plug is OUT OF WALL??