You definitely have my permission to dump the project but maybe there's a way to salvage a portion of it for a bag front, pillow top...or maybe a way to cut down each block matching centers before trimming? It would help to know how the mistake occurred. If you cut and sewed correctly, then the problem must have been w/ the squaring up to 8.5. until you know what went wrong, it will shake your confidence for your next project, but yes i know we've all been there...i googled the pattern and it looks difficult to me...what i saw was a tumbling block variation? if you have more than 3" pieces...just dice it up and save the scraps for something else! Over. Done. And you can move on.