2006 A4. The center seat belt has retracted all the way in. I need Ideas on how to get the belt tension to release?

The seatbelt "stop" (little plastic cap poped off last week). From what Ive read this is the result but have not found a working fix yet. The retracted seat-belt has gotten so tight I can not even raise the seat up from the folded down position without fear of leather tearing.

Can someone please explain how to access the retractor to be able to release it. I can not find a way that the back of the seat comes off. Next thought was the plastic at the top where the belt goes into the seat looks like an obvious route but not sure how to remove that without damaging it. IDEAS PLEASE!!! Shop wants 280 Euro to replace the retractor and I think the plastic stop on the belt is all that actually needs replaced.