My Champion does not get any Mastery Champion Points

Hey guys,

I am afraid that I became the victim of a bug. I wanted to ask, if anybody else had problems with getting champion points? I installed the game a couple of days ago and I bought Annie. A friend told me about mastering 1 champion first. So i played quite a few co-op vs al matches. Unfortunately, I didnt get any points so far and I have no clue why.

Who has an advise or knows what im doing wrong? Thanks for your help in advance.