Connection to Phone Failed

My device, not for the first time, has lost connection with my phone. The bell will not reset, when I press the bell to ring/wake it up, it goes red, flashes blue, gets as far as saying pairing information received the light turns red again then it just goes off. It doesn't matter if its plugged in or from the batteries, which I've taken out to reset it that way and uninstalled then reinstalled the app. Worse purchase I think I've ever made between these problems and constantly charging the batteries I wish I'd stuck with a bog standard one instead of wasting money.