I can only speak for Ultimate team because that is the only game mode i have played for the last 3 Fifa's.
Do not get mad, you are wasting your effort. The game is Handicapped as fuck.
Handicap (for people that don't already know seeing as EA has banned the topic from their official forums);
Basically, if you have a high rated team with players like Aguero, Messi and Ronaldo and you come across some one with a cheap ass team with Eminike, Moralez and Santana, then EA had the idea that in order to keep the game competitive player B (with the nasty cheap team) will get all of the rub of green. You won't get a jot from the referee, your AI controlled defenders and GK will turn into a bunch of pub team players and every bounce and ricochet will go straight to your opponent.
There is also Momentum which is when the opponent literally scores one goal and then your team will collapse and play shit, meaning they can score 2 or 3 goals in quick succession.
Scripting also plays a massive role, scripting usually occurs in the 45th and 90th minutes and is where no matter what you do to clear the ball it usually ends up with your keeper parrying it out right to an opponent who will score in the empty net.
It is for these reasons that i will never spend real life money on packs for players. EA have banned all of these topics from even being discussed on their forums because no one will spend money on a game that is fixed.