Retina IIIc repair??

In the middle of a cassette my Retina IIIc "locked" up: couldn't advance the film or release the shutter. It had performed flawlessly for many cassettes before this, and yes, I did check that stupid film counter. Does any one have experience with repairs on these? Who's the go to person for repairs?

Other than that and a non-functioning meter the camera is in lovely shape, I even scored a ER case in beautiful condition, several filters and the Kodak lens shade. I'd love to get this beauty back in service.

Thanks