And then what?
Let's ponder this for a moment: You live in a country where there is one dominant party. A party that does not really represent you, but it seems to have a lot of support and backing because it does have the majority of votes. Maybe also because it's known that whoever exposes himself as someone who doesn't support The Party has to face some strange problems suddenly. Like, getting laid off for no good reason (explained as "economic reason").
Now you notice that your vote for $competing_party was counted as one for The Party.
What do you want to do now? Complain that your vote was counted wrongly and risk your job? Of 100 people "wrongly" counted, maybe one will have the guts to stand up and risk his future for the sake of democracy.
Sorry, but there is no cure for computer voting. It just isn't possible to make it democratically robust.