Inserts are such a kludge. Less fluid, less piston area, less throw, etc... Just plain a bad design.
What is interesting is that the example photos show what appears to be an unscrewable cap on the cylinder which means they should be rebuildable, revalvable, etc... At minimum, the insert should be designed to use the cap for retention, not a bolt through the soft bottom of the case. I used to rebuild the ones on my Lancias that had a similar cap.
That said, take some pics of yours. From what you have said so far, the bolt on the bottom got loose, and then beat the crap out of the bottom as it continued to loosen. I'd bet you need a new strut.
You should just buy Scott's Koni struts, as should all the other people (Cody & Van
) looking for blown stock struts. Or pick up some cheap coilovers.