Kopaonik is Serbia's main ski resort, and the two OktagonBet counters here are resort addresses rather than town ones: one at Hotel Milmari on Stefana Prvovenčanog, the other up at Sunčani Vrhovi.
The Milmari counter stays open to 02:00, which fits a place where the evening starts after the lifts close. The Sunčani Vrhovi address is being confirmed and its hours are not listed here yet; in a resort that empties between seasons, that is worth knowing before you walk up.