First of all you need to use internet/mobile data from your phone.
1. Plug your phone with cable and open tethering to share mobile data to your laptop.
2.Open terminal and test internet by -> "ping 126.96.36.199" command.(You can stop it by ctrl +c).
3. Update the packages -> "sudo apt update"
4. Upgrade the packages -> "sudo apt upgrade -y"
5. Restart the laptop.
If it is sill not ok,
7. Upgrade distro -> " sudo apt-get dist-upgrade"
8. Add repos -> "sudo apt-add-repository multiverse && sudo apt-add-repository universe"
9. And go to no 3 again.
If it is still not ok, enter -> "lspci" command and send us the output please.