It's usually a USB combo modem and wireless networking adapter that connects to the nearest cell phone tower.
Have you dropped the internet stick since it last worked properly ?
Your internet stick and/or the USB cable to your cell phone may need to be plugged directly into a USB port that's built into the laptop.
Troubleshooting USB device problems
See Response 1:
Your laptop probably needs to be close enough to the nearest cell phone tower in order to get a connection to the internet.