That was a very strange response. Since we haven't seen the original advertisement it is hard to say if the email makes sense or just a lot of double talk. When you buy a "layer cake" you expect all the pieces to be the same size - but if you buy a "grab bag" you don't know what the sizes will be. Their e-mail almost sounds like they buy remnants from the Mfg and just sell them without any other processing on their part. Their comment that wool processing changes the size of the product is weird - I have bought a lot of wool in my day and I bought it by the yard - it was always the same 36 inches as when I bought any other fabric. If you buy wool before it is processed then there could be a variation.
So it would be interesting to see what the ad said.