my speaker on my Technique is distorted?

my speaker on my Technique digital piano is distorted. If you plug in the headset and wiggle it, it will sometimes stop. it has this sizzle sound when you play and you can hear it slightly like a lull, when you are not playing. it is not a continuous thing, it sometimes quits and the sound is perfect, then it can come back and sizzle again. (sizzle, meaning when i press the key down, it is a distorted sizzle sound) along with the note sound. Does anyone know how to fix this?