they wont replace the copper cable they never do, they will just do what is enough to get the line more stable maybe at the cost of some sync and tell you that's the best your line can now do, sadly to BTO / BTW it doesn't matter if it's ADSL or Fibre they treat it just as badly as long as your not way below your estimate ie in the red in the BTW test they will do next to nothing they couldn't care less what sync you had in the past.
