Hello friends! I bought a MDR-AS600BT last October in Munich (Kalfhof. Gallery). I started to use it on Munich Marathon 2015 and it was very good! Bluetooth, wireless and good sound quality! After a few races, the equipment began to show some flaws in the left unit (L). Now, just the right unit is running. I reseted several times without success. All songs are stereo. I tested other headphone with Bluetooth and wireless with my Samsung Galaxy S5 and work well. Anyone know how to fix this? Thank you.