That is the bla-bla-bla I just received from the Nordeus support:

Thanks for your report.
We are very sorry you have faced this situation. Unfortunately the connection with the server
broke during the match and the result has never been saved in our database. This is why the
match needed to be simulated.
This current result, the one that is displayed in the “Fixtures” section in the game, is now the
correct one. It’s settled and we can’t manually change it.
We are constantly improving the Live Match feature. Our developers are already working on
this to make sure this issue won’t happen again.
Thank you for understanding.