Try during the day - looking at a distant hilltop or antenna etc. Of course, the image will be rotated 180 deg (basically it looks upside down). Now it should be easier to see something and work out what is happening. Can you see the focusser draw tube moving smoothly all the way in and out as you turn the knob? All the way to a stop point at each end of the travel. The lowermost screw on the focusser should be loose. It is a lock screw and, if tight, prevents the draw tube from moving. The upper screw should be adjusted until the draw tube is moving and not slipping. If it is too loose, the tube is not driven by the wheel. Is your eyepiece sitting all the way down against the focusser?
So what is happening to the image? Do you go from very unfocussed, through a focussed point back to very unfocussed again? If so, then we'd better start looking at the mirrors. But before that, have a good look at the eyepiece - anything odd about it - something out of alignment? Try another eyepiece?
OK, look down the tube and through the focusser with eyepiece removed. Is the secondary mirror in the right place? Has it rotated so it is not "facing" directly towards the focusser? Does the Primary mirror look to be tilted too much one way or the other.
There's a bunch of ideas to work through.
Please DON'T point scope at the Sun on purpose or by accident. Don't leave it unattended with children present while you have in out in sunshine.
I'm sure you'll have it sorted soon - these tube units are quite simple mechanically.
Eric
). Often through a night, one adjusts the tension screw a little to adjust for temperature change as well as for eyepiece weight. 
I hope they give you one for free! Plus an apology for your wasted time. However, 35mm, 50mm, 80mm 2" extension tubes all seem to be selling for around $29.
