glitch on the Serbian radar (not even)

I just came from Skopje to Belgrade this morning on the bus.
At the border the Serbian guys looked cranky because I have a lot of Kosovar stamps. They overstamped them all with "cancelled"and they did not give me an entry stamp to Serbia. The Macedonians also did not give me an exit stamp, but they often do not.
This means on exit the Serbians can cause problems saying I could have entered illegally. They cna fine me and even put me in jail.
I went right away to ask about this at the Canadian embassy and they said this can be a "big problem" and they sent me to a Serbian police office. When I was at the Serbian police and they said it is a "big problem" and I should return tomorrow morning at 9am with my passport and my bus ticket receipt. They said they don't have stamps.
I asked them what I should have done to avoid all this, because the border guards would not talk to me and I did not want to cause a fuss at the border.

So we'll see what happens tomorrow morning.
arg
lucky me