FLX1O issues

I reported problems with my FLX10 in June, I took it to a technical center authorized by you, and they said they repaired it but the problem continues, when connecting my 2 computers the FLX10 gives sound problems and when changing from computer A to B or B to A, the channel that is closed in the crossfader is activated and sounds horrible, please I need you to attend to my claim, my FLX10 is still under warranty, I have written to you previously and you have not given me any solution.