This is the message I got from them:
" HI i sorry to hear this. Cheryl is away for a family emergency and asked me get some details from you. The type of yarn, colorway, store you bought it at, and the dyelot. She said the plain blue the dye molecule is larger than the yarn molecule. When we get some of this info we will resolve this problem for you. Again sorry about this. If you would like to send us the yarn we will look at it and see if we can find the problem and we will get this dealt with for you. Thank You Kylie "
I only just got round to replying so will see what happens next. But that bit about molecules doesn't make any sense. You can't blind a scientist with science.