Command problems!!

I have a 2007 T spirit Prius, I have setup my mobile phone with this and set voice tags to names in the phonebook. When i press the "Talk switch" on the steering wheel the voice should say " please say the command after the beep" and then you would hear a "beep" from the speakers, allowing you to say "dial by name" as an example. All i get from my car after pressing the "Voice switch" on the steering wheel is" please say the command after the BEE" and then total silance as there is NO beep following this announcement.
So i unable to give any commands.

When i first brought the car this function worked ok, now i have had the problem for a few weeks it now bugs me, i have also tried deleting all user data, this has made no difference.

If i were to press the "phone button" on the steering wheel just below the voice button, this would bring up the phonebook on the screen, so then i could press the voice button and it would say" please say dial by name" and work correctly from there on. This just skips the first part.

Has anyone else had this problem and managed to rectify it, if so how?