One thing worth a try is toluene. I don't know if you can get the straight stuff locally but there are some so-called plastic glues (check places where model planes are sold) that are comprised of little else. The toluene will actually soften the surface of many plastics to which it is applied. This is when you press that surface to the one to which you want it attached. When it dries - and it doesn't take long - the two pieces are virtually welded together. It works especially well when bonding two plastic items together.