People who have deleted their social networks, how do they communicate with friends?

I have been thinking about deleting or deactivating my social media accounts but I have a doubt that invades me, 1) How do I communicate or hear from people who do use social networks? I have WhatsApp but in fact I don't have the contacts of several people I know...
2) once you stop having networks, how do you talk to the rest of your friends or family? Do they look for them by call or do they just isolate themselves from the outside world? Tell me what your experiences have been and what comments from other people I could expect if I do it.