XDJ-RX weird bugg/master not working

 Hello, i am in trouble. My XDJ-RX started sometimes to do not react when i click on for example FLANGER i mean he works correctly, but not light up.

Second weird thing is sometimes (after for ex. 3h of playing) my master is not working. There is signal on ch 1 and 2, in headphones but not even on MASTER.

I called to service and they told me to REINSTAL firmware, but how ? I can't downgrade to for ex. 1.50 and then back to 2.10. Please help me asap. 

SORRY FOR BAD ENG.