I don't think the seller deliberately misled you.
She says that the yarns are combined and indeed they are --
each strand is a separate full-fledged yarn, not raw unspun fiber.
Many patterns look wonderful knit with combined yarns
and many knitters make their own yarn combinations to
add richness to their projects or to achieve a different gauge.
It's pretty yarn -- just wind it into balls (which will keep it from tangling) and knit with all the strands. Try to use needles with fairly blunt tips and be careful to pick up all the strands with each stitch. If it's the right gauge for the Clapotis, go for it.
But if you must, contact the seller. She seems to be very open to resolving problems and has a generous return policy.