Hi, I bought a house with a new bathroom installed and i'm now trying to hang a cupboard against the bathroom wall. The surface looks like tiling but by drill can't get through it, it is a very, very hard material. I have tried an HSS, masonary and wood drill bit but the surface looks like I've only scorched the surface and no hole. Does anyone know what surface it might be and how or what kind of drill bit should I be using? Thanks.