The pump is running, the reservoir was empty, but now full. Broken line? Any thing else that may help me fix it, thanks

 

I had operation problems a year ago. Mine wouldn't go up or down, pump was running.
The fluid was leaking out. I had a bad hose ( expensive ) and the pistons failed ( really expensive ).
Had this taken care of but found the impeller on the pump sheared the blades.
In the past, this meant a new pump but VW has replacment impellers now and it was relatively ( for a VW ) inexpensive.
Pull your carpet in the trunk and look behind. Since you are losing your fluid, You should be able to see about where it is leaking from /to.
Just know dealer hoses are expensive and the pistons are super expensive.
You might be able to find the pistons on the net somewhere. I advise looking at used as a last result unless cash is a domineering concern, than take the chance.
Good luck.