This is what finally pushed me to delete my Facebook account too. Many people only use Facebook to communicate even if they have my phone number. So, they'd send me something on Facebook and expect me to read it there. Sometimes they'd even get angry if I didn't despite me telling them many times that I don't login to Facebook. I mostly don't hear from those people anymore and I'm fine with that.
This exact issue was the final nail in the coffin for me with Facebook. I was expected to use it as a primary means of communication and I refused. The hard part is, the people I don't hear from anymore are family.
