Taking a careful 2nd look, I think if you trim off the problem areas there won't be much left. Beside the dark patches, there are two areas of powdery white on two of the canes, including the "good" cane. All the leafy cane would be eliminated except for a 2" stub, and the other one would be left about 6-8". Still, if it's own root, it may come back next spring. Or am I imagining things, and you don't have to take off white areas and perhaps just a baking soda spray will eliminate the white patches. That will save more of the cane, but I think black patches will still take away the leaves if it's pruned below the suspicious area. Maybe if you do your best to save it and it still dies, you can request again a refund or a replacement if you include photos.
