My new phone is connected correctly , being linked to my modem exactly the same way as my old phone was (I also plugged in my old phone to check the cables were set up correctly) but no matter what I do I have no dial tone on either hand set. Each handset shows good connectivity/range, and have been fully charged, yet all I can hear when I press the 'talk on' button to make a call, is some white noise. Please help??