Polyester!! Beware!

I just received this quilt and I'm going to return it immediately, which is a shame since it is beautiful. I chose it because it says "cotton" or "100% cotton" FOUR times in the online listing, with no mention of any other fabric. It turns out the backing (the part next to my skin if I use it without a top sheet) is 100% polyester! If it had been the other way around (cotton on the bottom), I might have considered it, but would still probably have returned it - I try to avoid synthetics altogether because they are damaging the ocean environment every time we wash them. Also, it's not very soft, but might get softer with washing. I hope they make it over again with all cotton. But I'm tempted never to shop at Walmart online again, since I can't trust their listings.