How to mount Zooz ZEN15

I bought two of these https://www.getzooz.com/zooz-zen15-power-switch.html

The problem with them is they hang down so the circular unit that has all the Z-Wave capabilities and the like fall behind my washer and the signal doesn’t work very well. See my setup below:


So as you can see from the second pic, they would drop if I didn’t leave them sitting on top of the washing machine which also they aren’t really facing an ideal direction. I know I need to probably mount them somehow but was trying to avoid drilling holes anywhere. I did mount these to the back of the washing maching and taped it to the washing maching power cord but oddly no matter what tape I use the cords start sliding down tape and all until they are falling behind the washer again. Any advice/thoughts?