I am trying to simply replace a ceiling fan with a new single Hampton Bay light fixture. With the fan removed there are two sets of wires in the ceiling, two whites and two blacks. One set is hot...from the main, the other is not...from the switch. When I connect the light fixture to the hot wires, it works but the wall switch will not control the light. I know the switch is good. What do I do about two sets of wires from the ceiling and only one set of wires from my new light? I have tried all possible wire combinations.