long arm quilting machine?

Hello, I recently purchased a used long arm quilting machine. (Janome Artistic 18) I just had it all serviced. However, I am not able to get the bobbin thread to come up through the fabric to start or finish a project Because the upper thread loops on something there it breaks and gets stuck. I can see the top thread looping on top of the bobbin shuttle. If you have any suggestions, I will appreciate it. It is driving me crazy.