Google Schwintek slide synchronization and follow the instructions on how to re-sync the slide. Several good YouTube videos on this.
You need to reboot the radio. I would disconnect the chassis battery (red disconnect above accelerator pedal) for a couple of minutes and then repower the system. That should reset the radio. If it is still not working, give River Park a call.
You need to get an attitude adjustment around your local RV shop. Meeting with the service manager before repairs begin, never leaving your rig at the shop, and so on.
Roger & Mary
2017 Winnebago Navion 24V
2014 Tiffin Phaeton 36GH (Sold)