Welcome and thank you for allowing me to assist you! The radio may have "locked up" electrically and doing a battery disconnect/reconnect may reset it. So try this: Disconnect the battery negative cable for about 2 minutes and then reconnect it. Make sure that the ignition is off when you do this. Hopefully that will reset the unit. If it does not, then I am afraid that you will need to have the radio replaced. Hopefully the reset procedure will work.
I hope this information helps and let me know if you need further assistance with this.