I've taken the time to read through the responses in this thread.
You cannot expect PlusNet / BT to guess the internal cabling structure of the refurbished warehouse where you live. In purpose built or refurbished multi tenant/leaseholder premises the usual configuration is that BT Openreach deliver the service to the basement of the building. Generally delivery of the telecom service to the apartment is over copper pairs installed by the owner for that purpose. This helps to avoid extra wiring being dragged though the service ducts in the building during the life of the building. During the building/refurbishment the owner will arrange for master sockets to be wired within the apartment using the building cabling system. Given the shared occupancy of the building the owner's representative (caretaker) will need to control access to the MDF board in the basement where the external cabling meets the internal cabling.
In some less well organised buildings there will be no such provision for internal telecom wiring and the usual mayhem will preside.
The BT Openreach service provision does not allow funding for a pre-installation inspection visit in every case. They will normally attempt the install in a single visit, having pre-scheduled connection at the exchange end of things. Sometimes this does not happen smoothly and an extra visit would need to be scheduled. PlusNet have little control over this process other than raising the order against OpenReach in the first place and then raising reported faults via the OpenReach Help desk.
Is my understanding correct that you didn't use the standard equipment provided by PlusNet for the service? If so that will likely add to any installation issues.
You certainly have an aggressive manner in your postings and that is unlikely to help the resolution of problems if you use the same approach with the PN Customer support staff. Consider your ultimate objective. Do you want to get the service working or do you just want to throw your toys out of the pram?
My personal experience of PlusNet is that on the whole their staff are professional and helpful. If any member of their team is not helpful I know that they address the matter.
Now Zen, but a +Net residue.