The cable is probably off the spool. I've never had luck rewinding spools given the tension involved and creased cable. If you can't find solid instructions for rewinding the spool, look for a good used OE regulator over a cheap new one. IIRC, a same door regulator from any year 124 sedan will fit. You might need to splice wires with a regulator from a later car. The motor shouldn't be a big cost factor with a used regulator. Check the hinge area wires while you're in there.

Sixto
83 300SD can be yours
98 E320 wagon