Way Too Thin

I bought this rug to go over a wall to wall carpet in a game room that has a stain that will not come out. I had a previous rug down that was 100% wool and was starting to wear out. When I first put this down, it looked decent. The problems began when I started walking on it. It started bunching up! The carpeting underneath is a low pile so I didn't expect this. This new rug is just so thin. I thought the rubber backing would help but it is also too thin. I don't have a wood floor to try this out on to see if it still bunches up but since it is so thin, I would expect the same result. I'm either going to return it or put it outside on a concrete patio.