I feel your frustration. The same thing happened to me about 30 years ago. I think I got one of the first computerized machines that Singer made. It was a new model and I had problems with it from the getgo. I spent half my sewing time taking it back and picking it up. I finally had to go to a different dealer to get any offer to help. He was very nice and said the machine needed to go back to the factory. They informed me that the computer board needed replaced and wasn't covered by the warranty. That cost me 90 bucks. It sewed for a very short time and quit again. The same dealer sent it back again and that time they said it needed a new bobbin case(not under warranty) and cost me 70 bucks again. It never did sew right. It skipped stitches all the time, nothing helped. I finally got tired of it sitting in the corner unused and went out and bought a new New Home Excell 23. I love it and it has been a great machine. I'll never buy another Singer. I don't think they are what they are supposed to be, the new ones anyway. I'm thinking about buying another machine so I can have one here in the house and one out in my little barn where I have my sewing room. I'll probably go with a Janome. I think that is the same thing as the New Home. If I wer you, I would demand that they replace the machine now and not wait. I wish that I had done that years ago. I really liked the Singer when it worked but it never worked right.
Good luck, I hope you come out with a new one.
sassy granny