The only difference between US and EU units is the power supply (wallwart).
If you are not having luck getting it repaired locally, you should contact firstname.lastname@example.org, giving full details of where and when you bought it, and where you tried to get it repaired.
Be warned that it will be out of warranty and may have to come to the US to be fixed. There may also be some confusion at work – it is possible that there is nothing wrong with it – I'm not at all clear which buttons are not working.
Try restoring the unit to factory defaults (see UM) before doing anything else.