pioneeer ddj sr crossfader leaking is unpredictable

i currently purchased a pioneer ddj sr from a pioneer dealer and not in less than 3 months the crossfader leaked the pioneer dealer changed the crossfader and only after that in a month the crossfader started leaking again since then the crossfader leaks at anytime and its not predictable at times it only leaks for an hour then its all good it might even be good and not leaking for a week then the problem starts all again,. it leaks at the left side and i as well experience sound variations between the first and second deck please help