Man UTD tactic?

First Game for me for FM is FM12.. and i went to play with United.. I Just bought so many and played 4-2-4 and best result was 12-0 against Watford in the cup .. in the league 8-0 against Aston villa.. didnt know what was BBM for a mid.. just put it for fun for Douglas Costa for example.. but now when i play with united and use 4-2-4 i cant score much.. dont know why

The teams are starting to get used to your tactic. They set up their team to counter your tactic. You need to change it all up.

^^
ya but when I first played FM with that tactic .. I won against Madrid , Barcelona .. all of those teams..

its obviously a downloaded tactic . as akash said mate u need to alter your tactics becasu your opposition get used to it after a while