That’s an awful story. Very sorry to hear this happen to you.
Shame on MoFi! This makes a case that the traditional distributor / dealer model for cartridges is broken. One of the worst "middle man" arrangements in this hobby. Huge (multi -$K) markups simply for the privilege of routing an 8 ounce package to a buyer, with NO support & service heroics? No thanks. Completely needless. Of course your complaint against MoFi is not isolated -- it makes me sad they’ve gained such a prominent role in our hobby. I certainly avoid them for large purchases, and try to avoid them on small stuff too. Anyways, the dealer and manufacturer shouldn’t totally be off the hook here, either.
I agree with others -- don’t toss the cart out. It still has value. Besides the usual SoundSmith and VAS suspects, there are also other talented cartridge rebuilders. Take some time, look around. A good one should be proud of showing off their work. Ana Mighty Sound (France), Delta667 (Russian guy on the vinlyengine forums, though you can’t get to him these days), and Sửa Kim Than Cartridges (Vietnam, found him on Facebook) have all shown very impressive work IMO.
Like MSL apparently, Koetsu likes to hide. Maybe a cultural thing - so what? The effects are the same as ill will. That was part of my decision to buy more locally this time, and Grado is mightily accessible and mightily good to deal with. Great product, too.
I haven’t dipped into Grado cartridges yet, but what I have seen from them (I started in headphones), I have 100% confidence they would make things right in the situation OP describes.
One more anecdote. I have a local friend who made a HUGE stretch purchase for a brand new Ortofon Jubilee MC while we has working & still going through college. This was ~1- years ago. He wore a fuzzy sweater one winter day, and well wouldn’t you know it -- snagged the stylus right off. Almost in tears, he was ready to write it off as a complete loss. At our dealer’s insistence (sadly this dealer is no longer in the business - I miss him) he sent it back to Ortofon to "look over" and see what they could do (note: this was before Ortofon offered rebuild services). A few/several months later (Euros love their vacations haha) he got back a BRAND NEW Jubilee MC, no charge. Ortofon looked over the cartridge, and determined that the glue had failed before the cantilever, which is not how they’d intended it to fail. Or maybe they just decided to be nice and made up that bit about the failure mode :) So they replaced it under warranty! Shout out to Ortofon and Louis on that one.