If I were you, I would send the Leupold scope back to Leupold and they'll fix it even if you weren't the original buyer. I use a Leupold Vari X II scope on a 458 Lott which probably has a bit more recoil than your 500 S&W and I've had no problem with it. Any scope can break; at least Leupold will make it right.
I also have experience with T/C Recoil Proof scopes. Between a 460 S&W Mag. and a 500 S&W Mag. handgun barrel, I broke 2 of their 1-6X models (but they sent replacements with no problem) so, their "recoil proof" scopes aren't necessarily recoil proof. I believe the construction of their 2-7X and 3-9X Recoil Proof scopes is of higher quality; they'll probably hold up to 500 S&W recoil.