Hello,
I am very mad atm,

I had a problem with my car when trying to start in the cold weather and logically I had it taken to replace the glow plugs. I took it to the local garage and had them work on replacing it, I was there watching them and when the mechanic started on screwing off the glow plugs I told him that maybe he should use some lubrication spray to loosen them up a bit, which he did but didn't wait enough time.
Anyways he managed to replace 5 glow plugs out of 6 and the last one's screwing mechanism and head got broken off and only the shaft remained in the hole. The mechanic tried to spray a lot of lubricant spray and used pliers to try to take it out but it would get out. Only the shaft of the glow plug remained I waited for like an hour for him to remove that single shaft but couldn't do it. Finally, he said it was best to just put the old screwing mechanism on top and just leave it unplugged and put everything back. I paid less money then we agreed since he couldn't fix all of them.
Now I am stuck with 5 cylinders getting all warm and cozy and one being unplugged and cold all the time. Is there a way for me to somehow remove the shaft that is stuck in the glow plug hole, the mechanic tried really hard using pliers to remove it but he said the glow plug tip might be so expanded from overuse that it's impossible to remove it and worth to leave as how it is.
Any help is appreciated thanks!
P.S. I think stuck glow plug looks something like this