That is not necessarily true. My Phone line was always with BT but I has ADSL with PlusNet. When FTTP became available I ordered from BT and for a period had both ADSL from PlusNet and FTTP from BT. The ADSL was only disconnected after I contacted PlusNet to request the termination. If I had not done that I would still have both available. I only ever had one Phone line but I did switch the calls from the copper to the fibre during the process.
Well maybe you have been unlucky. In the last 6+ years with BT broadband I've few problems. FTTC speed is not great but I am a way from the cab in a small village, I upgraded to FTTC on the website, couldn't have been easier.
BuckleZ (fountain of knowledge)
Sat 14-Nov-15 16:56:31
Been with BT since VDSL came available in 2013 - never had an issue, fantastic service. Had one glitch where an engineer disconnected my pair in the cab by mistake, sorted quickly and compensated for it.
Speeds always great, never any problems at all.
I had no problems until i moved to an house with fibre to the house then it went tits up. they even sent open reach out and they said they would need to dig the garden up to install it which they said was fine. Then nothing happened.