This is what I said to the other mate, you can try all formations you want, it will not work if, your players don't give you enough contribution.
You can have a full 6* team and this can happen.
If you want help, add better a pic of your team stats page, this page that show all goals, assisiances and MoM of all players.
Then, to see quicker who are more determinant players, play a friendly vs a 1* team, if a player don't appear during 1st half change it.
Post both things and with this info one can see more or less what players need to be changed.