I opt for the smiling, friendly approach and it seems to work. We regroup and are told (or at least we assume we are being told) to come back in the morning with a Serbian speaker.

我用笑脸和好声好气的办法奏了效，我们重整旗鼓，警署要我们（或者至少我们认为是这样）回去，明天找个说塞尔维亚语的人过来。