After 2 attempts to stitch in the ditch my top fabric seems ok but my backing fabric ends up in bunches as I finish a line of sewing. I have removed the sewing - re pinned twice and it is still happening. As I near the bottom of my quilt it ends up looking like a swag curtain (hopefully you will get my drift). Could it be a problem with my machine tension or is the backing fabric perhaps not up to snuff. It does not quite feel the same quality as the top but when I bought it the bolt said it was quilting fabric. Please I need some help!!!!!!!