You do not mention the car make or model...
When this happened on my Golf (twice) the winding gear had broken with repeated stress.
The mechanism without the drive motor sits on a metal plate - cost about £50. I got a mobile car lock-smith to supply the parts and repair mine for another 50 on top.
It took him about an hour each time...
The Haynes manual gave details...
Peccavi
February 2011