Speaker jack won't work?

I recently bought new speakers and the jack/connector part that plugs into my ipod acts really weird. Depending on what way it is twisted, different speakers will or won't work. There's a 'sweetspot' of sorts that gets all of them to work, but moving ipod or handling the jack in anyway will distort it again. What are my options?? I don't think it's under a warranty since I bought it off amazon.