Another one @styggpyggeno1 will go after. The person who caused the damage, that is - not the watch. https://omegaforums.net/threads/a-warning-you-morons-and-do-it-yourselfers.37759/
For a stubborn caseback with odd notches, I have used a cheap Rolex opener and superglued it to a caseback …. Worked well. Just use acetone after the fact to release the glue. If you like, I can post a pic/videos.
I want to state for the record- this is why when a newbie presents a watch here and people say “show us the inside of the case back” or it’s recommended to ask someone on eBay to show the movement- I cringe.