Modern States voucher not working

[FloridaCLEPMom]

Has anyone else run into a Modern States voucher not working? My daughter's friend has been studying for her last CLEP (Biology) for days. She entered the modern states code into college board and it says "Voucher code was not applied. Please try again". She has reentered it multiple times. The code email doesn't say anything about an expiration date so that can't be it. She hasn't had this issue with any other Modern States vouchers. We aren't sure what to do. Should her parents just pay for the exam and then try to get reimbursed by Modern States? She really needs to take it tomorrow.

[Carnation]

To take it for free, you have to use the voucher.
So she needs to contact Modern States to get it resolved before taking the exam.