Then you should not use thier work in "your" mod.
Make your own fix insted of stealing other work without crediting them.
No, you make a patch that does not include that contect or you, or someone else, re-make the fix for your mod.
See the above comment.
And you took contect that was not yours allong with you, making you nothing more than a common thief.
Incorrect. Mods often are released with the understanding that they are not to be modified or used without the permission of the author - when this is not the case they are, most likely, released under the Creative Commons "copyright." Unless that is the case you should not presume that you can use the mod without permission.
No, you do.
Good for you. They, however, do mind.
As I said, they want it to be used as released - what you have done is to take their work and fuse it into something else, something that they do not want their work included in. Thus they are, rightly, accusing you of stealing their work.