A quilt teacher referred to sashes and borders as coping, meaning to cope with irregularities. Sometimes we have to accept that work is not perfect and do the best we can with it. Depending on how much off the quilt top is, you may want to adjust with the sashes or borders and let it be wonky a bit, leaving an explanation on the label. We had blocks donated that were stars and they visibly had a pooch of at least an inch which we corrected by reversing and sewing a dart to make it lie flat. we lost some points in the center but looked better than before. If it were to be hand quilted I could have worked it in, however we were tying it. Another option would be to create a design that would complement the top such as an applique on the border that would appear to be pushing the block over such as a cat or flower.