I'd try to find some more of the background...white Kona cotton is pretty much a staple for most shops...take one of your blocks with you for comparison. Go to plan B and replace 4 blocks...perhaps the corners? Go to plan C and redesign your setting to include some open space for a fabric that accents and could be used for corners and/or binding as well? Just do what we always do...make lemonade out of lemons...you'll come up with something...this is just a hill, not a mountain... I'm really wishing that this hadn't happened, of course, but I sense that you are going to make the best of it! Sending a hug to you!