Did you submit everything USC asked for when you applied?
Were you selected for verification?
Did you link to the IRS Data Retrieval Tool on your FAFSA, and if not…did you send tax transcript for those who filed?
Did someone NOT work at all in 2016, or not file taxes? If so, did you complete a non-filers statement?
What are they asking for?
Did you do ALL of these things prior to February 13?
https://financialaid.usc.edu/undergraduates/prospective/applying.html