You searched for: “nomophobia
nomophobia (s) (noun), nomophobias (pl)
The anxiety a person feels when out of range of a cellphone tower: Nomophobia is a combination of no mobile phobia and is a fear of not having any mobile phone contact.

There are many people who have become so dependent on their mobile phones that discovering the charge is too low, being in an area with no reception, or simply misplacing it causes nomophobia to rise to an extremely stressful level.