I'm newbie here,Are there any legit bitcoin mining company or basically most of them are just scam.
Some of them
are real, but before you are starting to use one I suggest you do your research about that site first. Most of the new people are too naive to do that and think they can be rich in no-time with it. And before they know it all of their savings are gone.
I agree. Everyone would need to do some research and be realistic about it. These days if you get 1TH/s don't expect a miracle. Neither would I recommend ETH or Monero mining on GM. The ROI is not good and the prices too high for their contracts.
If you wouldn't use an Antminer S7 with 4.77TH/s these days don't complain if your 2TH/s gets less and less profitable. It's a the same game as per hardware mining yourself. At some stage you need to upgrade if you want to remain profitable.