The bet was placed because you clicked on the screen to bet it.
Now unlike Stake, this provider (same provider for BetFury and others) only refuses your bet if the odds go in your favor.

For instance, you try to risk $1,000 on 1.50 and then the odds drop to 1.20 then the the bet wouldn't be accepted and the system would ask you if you wish to proceed with this new price.

However,

With this provider if the odds go against you and you chose to place the bet at 1.50 despite the fact that after a mili second the odds changed from 1.50 to 2.15 - then it's unfortunately too late and you would have to accept the fact the click of the mouse to submit the bet was accepted by the provider and that's what happened here.

Yes, it is annoying, but unfortunately their system don't refuse bets if the odds go against you, only if the odds go in your faovr then you have to re-accept the bet.