Hello, I had the same thing happen on my 01 v70 passenger rear door. On mine the top pulley a little piece of the pulley broke and my cable came off of track. I checked with volvo and a the didn't sale just the cable. I talked a independent volvo tech and he said the whole regulator had to be replaced. It is riveted in, so yopu have drill out the rivets, remove the old regulator. Put the new regulator in and where the rivets are either re rivet using heavy Volvo rivets or use small machine screws with bolts and washer. It took me about 3 hours for the whole job. The part was $325 from volvo, so I got a used for $125 from Volu Parts. I hope this helps. I believe at the volvo service dept it was a $650 job. so, I it worth it to do it myself. I hope this helps.
Thanks
Dennis