As others have indicated, there are a few different possibilities here.
Is there any chance you can shoot and post a photo or two of the problem item? That might help identify the best means of repair.
It took a long time to get that nut on. I used a screwdriver to jam the nut and was able to wrench the bolt on very tight. If I get a J-Nut in the future I will take pictures and post them on before and after fix.