handset goes dead when I recieve an incoming call?

I bought a Telstra V850A hands free phone from Dick Smiths less than a year ago, for the last few weeks when I get an incoming call I pick up the handset from the cradle and the handset goes dead, no charge, then it comes back to life but by that time the answering servic kicks in and all I get is the echo of my own voice and I lose the call. I would expect better from phone bought brand new from a reputable dealer, any suggestions? Could it be I need a new rechargable battery for the hand set?