Many many many years ago, a police force had problems booting a server with a certain very old OS (they openly admitted they had done something wrong during the install), they would not allow remote access and did not want someone going onsite due to security.
They offered to send us the server which they did. On receipt it did have a boot error, but this was different to the reported one, they had taken out the HDD with the bodged install and destroyed it.
We sent them the chassis back, they put in a new drive and installed the OS which worked fine and they were very happy with the service they received from us.
i.e. you may not want to rely on the internal expertise.....