Legal Question in Employment Law in California

If you made the call on a company phone it sure is. You have no right of privacy in what you do on company equipment, and damned near none in anything you do on the job. About the only exceptions are dressing rooms and toilet stalls. Anything else they are free to track, record, monitory and anything else you might not like. Your workplace is not private. I bet you posted this question from a work computer too. If you did, they can look at this too.

On company phones you have NO privacy rights, and can be terminated for personal use of phones, computers, or any other company equipment or time. So, yes, they can check your use.