I have never called Lyman, even though I have a bunch of lyman stuff, but most of it is no longer in manufacture. I've been lucky and haven't needed anything.
My only dealing with Redding was 6 or 7 years ago. I needed all the screws for a (1980s manufactured) Saeco mold, it was in tough shape, but cavities were fine, I bought it at a gunshow. I emailed and conversed with a sales rep...I must have gotten luckly, as he understood what I needed, I offered to pay, he said that wasn't necessary and sent them out, every screw was correct.
another one ... CH4d.
I was given an old set of 222 dies from a fellow forum member, he said the expander plug was bad, but dies were in great shape otherwise. The Expander had been attacked with a vicegrips and was cracked and threads on stem were damaged. I called CH4d, they said no problem, and quoted me a price, I asked if they take paypal, he said CH4d didn't, but for such a small purchase, he said he'd accept the funds through his personal account and sent the parts out.