There are tons of treads on this. An early c5 is to be recommended.
But don't expect to be able to win as Black every time. If White don't want to play it can be hard for Black to win in any opening. Maybe try to ad a more asymmetrical opening as a second choice in games where you foresee this. Like 1.d4 f5 or 1.d4 c5.
It seems that as black, one of the most challenging openings my opponents play against me is the London system.. I can't seem to break it and it's one of my worst openings in terms of win percentage (~40%). Any suggestions for simple ways to play against the London?