OEM Head Unit issue

[OlyS4]

Hello, I have an '02 X5 3.0 with the in-dash CD receiver and a changer in the rear.

Has anyone had this head unit repaired, or repaired buttons themselves? The "Mode" button no longer works so switching from Tuner/CD/CD Changer is impossible and we can now only use the in-dash CD and switch to the tuner by pressing the "FM" button.

Anyone with this issue or experience? Looked on ebay for a replacement, but they all go for around $175 and for that I can get a better quality aftermarket head unit and the required adapters, but I would like to use the CD changer as well.

Thanks!