I purchased the qc 30 in December 2017 in Germany. Since the 5.5.18 the headphones are no working properly. I can't turn them off, pressing the multifunction button lowers the noise cancelling, the volume buttons don't work and once in a while the volume lowers by it self. I'm in israel so and there isn't a specified support address. Please help me with this problem. Thanks in advance. Gadi.