Just sold a cardi on eBay that I listed as cashmere blend, which I thought was accurate as that's what it was, I think with angora and cotton. Didn't put percentages and buyer complained and left neutral feedback saying that the 15./. Cashmere wasn't enough to warrant being called "blend", and also complained about size, label said 14 but was too small for her.
In future I will list clearly any percentages especially if cashmere is involved!