The back button has stopped working. Following the instructions that we have here, that was the same solution: follow the instructions, send your serial number, etc, I got a ln answer that my watch was out of warranty and I have to pay for it by myself. I'm wondering if Samsung is taking care about that. I would by a new version of the same brand that has several complaints about the same issue? In my opinion you (Samsung) should know that it costs a lot of money should and give us a better treatment.