Help needed please! MIXARS UNO - anyone know how to recailbrate the crossfader?

So I bought the Mixars Uno mixer brand new and after a few weeks the crossfader stopped working. The company is has recently been known for not responding to any contact so if anyone knows how to recalibrate the cross fader that would be very helpful.
So both channels on the mixer are on full volume with volume faders working, its just the crossfader is totally out of use despite it still connected it lighting up red with any motion sensed.
Any ideas please?

I’m not sure on the kallisto, but the old Galileo faders have a hole for tension and two little wheels on each side for lag adjust. If not, you can always drop in an Innofader.