Sounds like they may have given you the wrong starter
Basicly you have to remember the truck was running fine.
All that it needed was diesel.
But then the starter acted up.The only thing different than the time it was running is the starter.
Now that you know about the brace...
Get the right starter and brace install with new Starter bolts,plug the block heater in,remove as many glowplugs as you can remove easily.While they are out you can test them.
Crank it over in 30 sec intervals till diesel starts misting from the glowplug holes.When you are turning the motor over with the starter hold your accelerator pedal to the floor,that will purge the air quicker.
Once the diesel is misting from the glowplug holes replace the glow plugs and start the truck.
Then enjoy your truck again,watch the fuel levels.