Son's college won't refund FICA taxes

Does anyone have a solution to offer on this? I am trying to help my son with his taxes, and we have a problem. He was employed last semester (2020) and this by his college to work part time as a COVID monitor taking temperatures and asking health questionnaires of students entering university buildings. Under these circumstances, my son should have been exempt from FICA taxes from his paychecks, according to IRS Tax Document 9167 ("Student FICA Exemption). The college pulled out $305 in SS tax and $71 in Medicare tax before they caught their mistake and ceased taking the tax out from that point on. When my son inquired about the amount already taken out, the college issued a corrected W2 with the SS tax and Medicare tax merely zeroed out. No refund. Turbo Tax will not let us move forward on filing his taxes, because according to the Student FICA Exemption, he is due a refund of those taxes from the university. The university refuses to provide the refund and emailed him that he would have to request the refund from IRS. I am aware of the Form 843 and intend to use it, but he owes money on his Federal taxes and state tax (AZ), so he needs to hurry up and finish his taxes, so he doesn't get penalties for filing late. It is likely that he will not get a proper corrected W2 from the college prior to his deadline to file. How are we to handle this, so that he gets refunded the FICA taxes and still is able to finish filing his Federal/state taxes and pay what he owes there? This is so frustrating, because it could easily be fixed by the college, since they are the ones who made the erroneous withdrawals from his paychecks.