No one uses the phone app on their smartphones

I got into the car and left a place.  I drove for twenty minutes.

I arrived at another place.  I checked my phone there and saw that all the while, someone had been trying to get a hold of me so we could have lunch at the first place.  They had tried to contact me using the WeChat social media app which I don’t use while I’m driving.  

They don’t have my phone number.  Someone phoning me, using the phone app, can get a hold of me while I’m driving.