I can't speak to the 8594, but I had a truly bizarre experience with MSD over a defective MSD 8595, which I think is the same distributor but with the vacuum advance.
The magnetic pickup failed several times, but the last time MSD kept the thing for months, and gave me several completely contradictory and outlandish explanations. They told me it was defective and they would send it back EXCEPT they didn't have any new shafts and they had removed my cam gear (I had a melonized iron gear to work with my billet cam) and that the shaft had been drilled too many times (as in twice, once by them, once by BarryR to put the gear on for me) and the couldn't re-use that shaft.
This went on for weeks - I couldn't believe that they had no shafts and couldn't get any, and when I asked them to just send me a new distributor, I was told they didn't have any of them either.
I really felt like I had called a lunatic asylum and the inmates had got control of the phones. In the end they suddenly told me they had NEVER taken it apart and it worked fine and returned it to me. I sent it back to Barry for a refund. Even though MSD (Holley) agreed to a refund I never got one.
You will probably need to find another distributor and eat your loss.
