OK, there is something you can try if you have the radio code for the car. The display can sometimes be reset by disconnecting the battery for around five minutes and then reconnecting again. This allows the capacitive charge in the display to deplete and can sometimes get it working again.
I've purchased a used Ford Mondeo and the AM/FM button does not work, the radio does as it was on when I got it, but after I pressed the other buttons aux and CD I can not get the radio back on. I removed the button and the soft rubber bits when pressed, do not have an effect. (they do on the other buttons).
Mondeo 2010 plate with 6000 CD: Bluetooth & AUX suddenly stopped working - Turned radio on and held power button in for about 8 to 10 secs and the the display went blank. Lifted finger off power button and display lit back up again. . 328 324 31 267 368 78 31 273 322

ford mondeo radio display not working