What's wrong with just:
repli Char -> Integer -> String
repli _ 0 = ""
repli c i = c : repli c (i-1)
This function is in curried form, but if you want to avoid uncurry just write it in its uncurried form:
repli (Char, Integer) -> String
repli t = if (snd t) = 0 then "" else ((fst t) : (repli ((fst t) (snd t)-1))))
