Is the ‘fibre’ you have switched to, FTTC ( fibre to the cabinet) ?
Assuming it is, and you had service up-to the day of the supposed changeover, and you now have no broadband or phone service, suggests that the OR engineer has made a mistake, that mistake is not necessarily detectable by the ISP testing the line.
If you have no dialtone at the master socket, you need to report the fault, if the line tests OK ( even though it isn’t working ) you would have to insist on a visit, and when you are advised that charges could apply if the problem isn’t external to your property , you would accept this potential, after all if you have established the problem is external, then you won’t be charged, the ‘warning’ is just that, advising you that your internal wiring and equipment isn’t Openreach’s responsibility, but the external network is.
