Q: Apple trying to call, don't have phone.  Help!!!

my iPhone has been misplaced and I cannot sign onto find my iPhone because I have two separate apple IDs on my devices and I cannot switch between the two without risk of losing everything. They tried calling me, but I have no phone to answer. I tried to request communication through my iPad...FaceTime, imessage, but there was no real way to ask for this or message them. i just want to talk to someone