Please Help ( pcm locked and can't reflash by dealer)

[Mustang1981]

I bought a ford mustang gt 2016, later on i discovered that the car has a tune on it by unknown device. I tried to return to stock by ford ids shops no luck, and took the car to authorised dealer and they were unable to log on to pcm to be able to flash and said i need a new pcm with harness which cost aroud 3500 dollar.
I took the car to tuning expert which he found that tunning file belongs to diablosport handheld device.
So my question is, is it possible to return the car to stock file if i bought a diablosport device and technicians support will send me file to recover ford oem file.
Pcm file (strategy file) on the car name D7CEE9V

[mikel]

anything loaded to the pcm from a diablo device can absolutely be flashed by any dealer or IDS user, nothing we do would keep that from happening.
How did this person determine the tune came from a diablo device?

Sounds to me like it came from a different device that allows changing calibration info to keep factory tools out....