it worked for a small while though
after that it didn`t,i deleted the connection
and then i tried adding the device again,but it wasn`t recognized
when i start the headset,a short red flash appears and then the blue one
both devices have bluetooth activated but won`t recognize each other
help

Is the headset compatible with the Blackberry 9900? Check the specs on it.
what type and model is it?

it`s headset HS-700
and it worked just fine for 2 hours,then i disconnected it
and when i wanted to reconnect,it never did

The headset is compatible so I would make sure you delete it on the phone and re-do the pairing. Make sure you know the security code if you changed it. default is 0000

http://docs.blackberry.com/en/smartp...837-001-US.pdf