Saving a few dollars by buying a junk battery and ruining a $$$$ camera does not make sense. I bought a used camera one time with exactly the same issue, junk battery swollen up and jammed in the camera. In my case, the battery was long dead, so I took a electric drill and drilled several 1/4 or so inch holes in it until I could finally take it out in pieces. The camera was not very good anyway (A Sony), so I was willing to risk damage. It turned out fine.
In your case, I'd contact the battery seller and see if they will pay to have Canon fix it. Realistically, it may not be totally dead, and my solution might cause a explosion or severe overheat and ruin the Camera.
Have Canon repair it, its a expensive lesson learned.