Thank you for your replies.
Dale, they went in spot on at the soil level...no rodents or predation or signs of insect damage. But the leaves are looking rough...please see here: https://permies.com/forums/posts/list/39813#309973
Leila, I was a bit more arbitrary in my e-mail to them, as per below:
"I just wanted to write to see if you might take some time to discuss the situation and potential resolutions that you can provide. I'm not sure if this would be a situation where replacement trees or what other options would be appropriate or some such consideration. "
I'd honestly rather order from some place else than have the trees replaced by the nursery, but I did not see any allowance for that in their guarantee (one growing season).
I did not reply yet indicating how close to the graft the damage is but I did it find it odd not offering some other solution or diagnosis. I got the vibe of "it's cool or cut it" the way I read their reply email.