When I had a similar situation with my mom, of tech gear sliding/being pulled off of a piece of furniture by attached cables, I got some of the rubber grip material from the dollar store and placed it on there, and the device in question stayed put.

At Dollar Tree I've seen two kinds, a roll that you can cut to fit (for lining kitchen drawers to keep things from sliding around when opening and closing them), and thicker round pieces. I think the round pieces are actually intended for opening jars, but I've used them to keep stuff from moving, because it's actually the same material, only thicker.