If your iDECT X1 handset has recently failed, then don’t throw it away (yet). A common problem with these handsets is that the batteries tend to fail after about year (sometimes less unfortunately) and the simple solution is to replace them.
These fairly inexpensive 2/3 AAA batteries could be the life saver your iDECT phones have been looking for. Whilst these are not always the answer, it is a good first start. Which if it works, then it has been money well spent and should see your phone going for another year or two.