I have purchased tickets for Frozen and advanced parking thru ticketmaster. All of the tickets including the parking are indicated by 'will call' on the mobile app. I have been trying to obtain an answer from customer service and there is no help.

You can pull up to the front of the theater and go to the will call office and get your parking pass along with your tickets. Then get back in your car and go to the parking venue.

The earlier answer is correct, but to be more specific: "Will Call" is picking up your tickets from theatre on the day of the show.

'will call' indicates that you are required to pick them up at the theater