although an obsolite model BT still offer a help line at £1 minute but most calls last less than 3 minutes.(09065533505) a factory re set of 2150 may sort this problem. Unplug unit from mains, wait 1 minute then hold down page button as repower the unit and keep doing so through a series of long and short bleeps. When they stop release page button and then press it 5 times quickly. There will be a confirmation tone. You may have to re register your additional handsets.
Bill, April 2005