XDJ-XZ console problems

Hello. I have the XDJ-XZ console

  The console worked normally and only had a problem with one channel on the headphones. He went to an authorized pioneer service in Greece and they told us that the MAIN board needs to be replaced. We left it there for 3 months and they didn't change the circuit board. We took the console back and bought new same MAIN with same codes from Australia. The installation was done by a technician (electronic) and we have 2 problems.

1 The headphones now don't play any of the 2 channels at all.

2 The sound now plays distorted even with low levers on all outputs.

Any help on what could be going on?

Sorry for my bad english