Do I really have to take the entire assembly mount out of the counter ?

EDIT: Delta/Brizo is sending a new cartridge, and we will try that. Thanks for all the assistance.

Plumbers, please help! I had my main bathroom redone. I hired a reputable contractor. We bought our fixtures at a plumbing supply store. After talking to them, we liked the idea of the thermostatic shower, as we had some small issues with the temperature changing when flushing, but there's only two of us, so no big deal. Now, however, with this Brizo controller, we can't get a hot shower and a cold shower. We can only get warm and cool. If we have the plumber turn down the cold, the hot gets less hot. If we want it hot, we can only get to warm on the cold side. Is this how it is supposed to work? NO ONE TOLD US THIS. I hate this controller right now, and if I can't get this fixed, I don't know what to do.

I’ve got a leaky shower head and am trying to remove the flow handles to replace the washers/cartridge but can not figure out how to get the handle off. I don’t want to break anything and can’t find clear instructions online. Anyone have any recommendations? I took the caps off and tried a flat head and Allen keys in the hole to see if there was a set screw but no luck. Is it just pushed on and stuck or secured another way?