Hello, I am from Greece and I bought the m80 on August from ebay u.s. but haven't used it since then. I installed it yesterday in active mode and realized that the volume slider is faulty.. When I tried to lower the volume a bit the pickup stopped working regardless the position of the slider. Then I just knocked gently on the pickup above the slider and it started working again. Given the situation that I am from Greece what should I do to get it fixed? Is the warranty valid overseas?