Assuming that your example is correct and the tournament rules don't mention any further details...
If those three teams all have the same amount of points and the results are correct we can safely use the "direct confrontation" you've mentioned. In the real world it is usually a small table using only the results between those teams that are tied for points, in this case our three teams.
This means
- Team A has 2 wins, 2 losses
- Team B has 1 win, 3 losses
- Team C has 3 wins, 1 loss
This results in the following mini table:
Rank Team Pts Goals GD
1. C 9 8-8 0
2. A 6 5-5 0
3. B 3 8-8 0
So in the final table the order is C > A > B and the goal difference doesn't matter in this case.