when i press phone button it says handset in use.......its stuck on this message.

i have disconnected battery overnight to resett but nothing. car does have phone cconnectivity and used to work well. now its stuck

pls advise

 

I had the same message after I had removed the centre console, eventually found I had left a plug off behind the rear air vents in the back of the centre console, failing that, it could be the module that's gone bad, I "think" its in the back under the CD stack.