The other day I bought a brother sewing machine, but having problems getting it to sew The needles either goes up and down while fabric moves but just makes holes, or the thread all bundles up on the underside of the fabric, and then by miracle it does sew,it it is really loose and oulls back out i have tried changing the tension and holding the thread and fabric tight but it still happens. Do I need to tie a knot in the thread, any help please!