Meant to be 2 separate bets not combo, its same game so combo is impossible.
Well, we made the impossible possible. It's a feature 
If you put bets from one match into a combo, our system build different allowed combinations. A few bookmakers do this as well.
You get a premonition of this behaviour in the bet slip preview area:
So if you would add a third odd of another match, this odd would be added to both combinations - that's the difference from single bets.
I guess we have to explain it before submitting the bet slip because a few users already asked us if the did something wrong. We will try to express this rule in one or two short sentences.
In your case, you lose your bet anyway, otherwise I would increase your win manually
