I don't know who called but based on past experience it could be my phone network operator, as I had pest calls from an unknown number that turned out to be them. Only information known is an alert of a missed call from this number. No voicemail left. No sign of this call in my call log. I imagine it is a pest who hides their number and is up to no bl**dy good. In any case, I never return calls to unsolicited callers. Why does anyone who gets unsolicited calls return any of these calls? That's just what the pest callers want, isn't it? Be smart people and never return unsolicited calls. ;-)