Positiveparenting.com says that parents/ guardians should limit thier children on using or gaming. They sbould have agreement on time using it. Second is you should have the authority for them to follow you as a mother. They should believe you that if they wont follow you, they bmight be in harm.
In a family, you guys should have quality time, bondings and family time for them to lessen their time using internet or cellphones. This will cause them fulfillment.