How can I see what calls were automatically rejected with the "only receive calls from contacts" option? I've been expecting a call back about a job and I just realized I've had my phone on only receive calls from contacts. Is there any way to recover those past calls or see if someone else has called me?
You could contact your phone provider and ask for a list of all received calls in a given time period.

Since your contact list is on your phone, it means your phone still gets the call, checks if the caller is in your contact, and rings if it's in, or disregards it otherwise.

There might be a log somewhere, but checking with your provider may be easier and/or quicker.