Report "One of my handsets doesn't work anymore, it doesn't respond to pushing the keys as if the keys were locked. After I remove and replace the batteries it works for about a minute, but then it seems to " block" again. I already exchanged the recheargable batteries with those from another handset, but that makes no difference. Does it help if I reset it completely, and how must I do that? (especially when the keys don't work)"