No, they didn't. That has been offered to all who are booked on Concordia til the end of March. Costa has offered full refunds on any of their ships that are booked for those who have decided they don't want to cruise at this time. They have until February 7th to decide.
Costa has been back peddling on a lot of the help or lack thereof over the last couple of days. However, they did not offer 30% discount to those involved, only to those on future sailings.