Sorry you had a problem! Unfortunately, I have experienced the same. I was making a Hunter Star quilt and had strip pieced and cut as required, only to discover the book had an error. I had 96 pieced trapezoid units that were about 2" too small. If I had cut down the rest of the pieces to fit, I would have ended up with a crib size quilt rather than a twin. I couldn't find more of the same fabrics, and was so discouraged, I gave up. I still have the larger triangles, and will make something with them someday. I recycled the trapezoids and use for paper piecing. I'll just start it over someday.
Now, when I buy a book/pattern, I search for corrections on the book/pattern maker's website.