Where to fix a RF Lens?

[ingsy]

Hi! The back portion of one of my RF lenses has come off (I think it is called the rangefinder cam); I can put it back on - but the focus is way off. My local shop says they can fix it, but it would take a month or so. Does anyone have any recs for good RF lens repair? It is a MS Optical Perar Triplet 28mm f4 lens. THANKS!