Online Career Division up/down

Can someone please explain to me how the levelling up/down in divisions works? 

I just beat 2 ppl, both who were +2 divisions higher than myself. They both also beat me more times than I beat them in previous matches. 

After beating them both I went up 3/4 of a division. 

Then the third match I again meet someone in a higher division who also beat me more times than I beat him.  

I lost the game and went down 2 divisions. 

It's like it's designed for you to fail. You can win 8 matches in a row and then loose 1 and will then have lost all the progress from the 8 matches you won, plus more. 

Can someone from EA, like @EA_Mako , please explain this? It doesn't seem fair,