I don't know if this will work for you, but it is surely worth a shot at this point.
Follow these links:
How do I wipe the BlackBerry using Jl Cmder? - BlackBerryFAQ
What to do next if Jl Cmder will not connect and wipe - BlackBerryFAQ
In the second link, be patient, it may take multiple tries for it to connect if you're having issues.
See if that brings you back to a 507 error. Indicating no OS on your device.
If so, try to reload an OS on your device.