Ack! This stinks, I'm sorry they are acting weird!
So, to confirm, when you hit the button once it goes into messaging mode (one light, rotating around the face), after that you hit it again to confirm the correct friend, then you hit it as many times as you want to send vibrations, yes?
Is it happening both ways? You've tried sending from both devices? If that's the case we can walk through some other steps (and I may have more questions).