Shower won't shut off!

So hubby and I are replacing what was a tiny neo angle shower with a tub sized shower at our cabin (which is a 4 hr drive away... this is important). We gutted the old shower, purchased a basic Delta valve/faucet and proceeded to re-plumb! With the new rough in in place, we tiled over the plumbing, proceeded to install the balance of the new plumbing (cartridge, bonnet, etc). In the process of installing this I was fiddling with the cartridge to change the hot water limit stop location, and promptly dropped it on the tile floor! Needless to say the cartridge blew apart, springs and rubber washers flying everywhere! Fine... laugh!

I consulted the internet on how to put the pieces back together (after a big freak out by the hubby!). I'm fairly certain I put all the pieces back where they belonged, but after we installed the cartridge, handle, etc, and turned on the shower, it ran ok... but the water wouldn't shut off! Not even a little... NOT AT ALL!

Needless to say we pulled the cartridge out, turned the water off at the shut off set screws. Now that I'm back in town I sheepishly made a trip to the plumbing wholesaler and purchased a new cartridge. Hoping to get back next weekend and try my luck as a plumber again.

But until then........ my question to the plumbers here is... Is it the cartridge that is the problem? Or could there be some underlying other issue, like could something have gone REALLY WRONG in the rough in that will only be able to be fixed if we pull all the tile off the wall and start over??

Any/all advice is more than welcome. Thanks!