I got these as a Christmas present with no gift receipt. I was really excited when I got them. I tried to pair these headphones with my cell phone (Sony Ericsson w580i), worked great.... for the first minute, then all sound was cut off. Even when I turned off the bluetooth and unpaired the headphones from my phone the sound never came back till I restarted my phone. I tried un-pairing and then re-pairing my phone to the headphones about 3-4 times and the same thing happened each time. My husband has the Blackberry 8830, I had him try to use my headphones, SAME ISSUE OCCURRED, worked for a minute then stopped working all together.If I could return these headphones I would in a heartbeat, these are a complete WASTE OF MONEY!