Phone lines not connecting to Internet line

[Wayneroberts]

Even since we have had our new fibre boosters we have no signal on our handsets for our phone line. The only two that work are those closest to the router 

When we walk from the front room to the kitchen which is less than 4 meters we loose signal and phones cut out which can mean the calls cut out also.

Prior to the new fibre our house phone sets worked reliably across the house 

Please advise as we have had a catalogue of issues with the fibre. Just when we thought it should be fixed we have this issue still 

[Mark39]

Are you using cordless DECT phones with a base station plugged into your broadband Hub?