How frustrating for you! There are a lot of good suggestions here and I am going to add two more (thought it was just one, but have already thought of another :-/ ). 1) since you have a shop to service the machine, check with them for their suggestions - tell them what is happening if you didn't do that when you had it in for service; 2) very helpful tip I learned in my last quilting class - reduce your PRESSER FOOT tension (not the thread tension) to 4 or 4.5 - it doesn't 'push' the fabric around and made a huge difference for me. Good luck!