i would also encourage you to take it back and show them the problem. I use a variety of needles, depending on what i'm doing, a variety of thread (gutermann cotton and polyester/ king tut cotton/aurifill cotton) and have no problem at all. the only issue i've had is when i didn't realize my leg was ever so slightly touching/moving the knee lifter. I was ready to bring the machine back until I realized it was the 'nut next to the knee lifter'........ :-)