Why won't my SoundBot SB220 Stereo Headphones turn on?

My SoundBot® SB220 Bluetooth Headphone won't turn on, or make any signal that it is working, when I press the 'multifunction' button that is supposed to turn it on and off. I'd been having trouble with getting a response from the headset before, but it had always eventually turned on. Now it seems to have stopped entirely. Although it seems like a bad switch, I can feel the physical switch operating when I press the big button. Can anyone help?