The description mentions cotton / poly broadcloth, which is usually sturdy. Maybe, if you call customer service they might say returning is OK, if the quality doesn't need your expectations.

Sorry you think the fabric is thin, but if you are a quilter and are going to quilt the blocks they cannot be real thick. I am a quilter and only use 100% cotton fabric. These quilt blocks are a cotton/broadcloth combination and that is a little thicker. By the time you add batting and backing to the stitched blocks you don't want it too thick or will be very hard to quilt. Hope this information helps. I purchased some Dempsey quilt blocks for a friend once and they were fine. If you are still concerned contact Dempsey and discuss it with them.