I have a brand new singer machine and purchesed a walking foot for it from the dealer. The first picture shows the mark the walking foot left on the material when I tried to sew in the ditch. The mark cannot even be rubbed out. The second pic shows how uneven the rows looked using this walking foot. Kind of a seesaw affect. Since I have never used a walking foot before I was wondering if anyone else has had this problem. Promise me It was installed correctly. When I take the walking foot off and look at it with the teeth in the down position,one set of teeth is lower than the other and if I set it down, it tilts to the low side of the teeth. Any clues?