DDB,, I will say that in general,, negative comments around here only come when folks feel the other poster started with negative comments. You are new here,, and occasionally when a newcomer starts off with negative comments,, they get suspected as being a troll,, trying to cause problems.
All that said,, if you were offended,, I will apologize. However,, in your first post,, you failed to give good details,, and "attacked" the customer service for them not treating you as you thought they should. That,, & the comments about a bad design.
The design is a tried & true proven design. But,, you have mentioned twice that the magazine the won't work is "a different design." Could you please describe the differences in the "good" magazines vs the "bad" one? You mentioned the gun is a MKII. Are you sure you have a MKII magazine? It could be an older MKI or Standard magazine. Or possibily a 22/45 magazine that has been modified? Maybe somebody else tried to customize the magazine?
If the magazine is just old, worn, damaged etc,, I too would agree that Ruger is correct in not replacing it. I buy a lot of magazines for my competition guns,, and I do so knowing I will be dropping them, throwing them etc,, and they will eventually get damaged from MY abuse. If a previous owner abused the magazine,, and as you have found,, new ones work just fine,, then it's obvious that the mag has issues. But to bash Ruger CS for not replacing it,, may be a little out of line.
Thanks for more details in your second post,, but I'd love to hear about the differences, Pics would be even better.