I am back to the film game after about, oh, 15 years or so, with mostly my Mamiya RB67. However, I also own my late grandfathers Kiev 4 with two Jupiter lenses. This eems like a really nice and cool camera, with a weird multi-focal-length viewfinder and a leather case, but also with a broken shutter.
Where is the todays go-to place to fix manual cameras? I don't mind sending via mail (I suppose this is the only way nowadays).
For a Kiev, the best recommendation I've gotten (haven't actually done it yet) is to send it to Oleg's shop in Ukraine.
This is somewhat specific, because the Kiev family of 35 mm rangefinders through model 4 is a Contax II (or III, or IIa/IIIa, depending on the Kiev model) built on the original Zeiss equipment relocated to Ukraine as war reparations, originally in part by Zeiss employees who went with the factory -- and Contax RF cameras are quite specific beasts to repair. Complicating this is that a number of the better Contax repair folks just refuse to touch Kiev cameras.
For you, in Croatia, Oleg's isn't half the world away like it would be for me; shipping will be faster. You can still expect a significant lead time (good camera repair shops tend to have backlogs), and it won't be cheap -- but it'll be a lot less than (for instance) a couple of the top American shops, and literally years shorter waiting list.
I had my Zenit-3m and Praktina-II repaired by Фотомастерские РСУ in Moscow: http://kamepa.ru/remont.htm
I was happy with the results and even more with the price.