Some company here from Philippines wants people to invest $100 get $300 for next month, then they'll do the projects like making "fish ponds", "plant banana trees", "get cheaper products and sell for high price", etc.... When the company knows their money will wipe out due to their unsuccessful projects, they'll run the money from investors without notice it. Now, you want the investor (who got scammed) to get money for free by doing bitcoin work, how will you explain how to do it?
You do not invest in such kind of schemes and if you do, that's your own risk and shows how stupid one can be. All sites/companies that promise one Bitcoin or 1:3 in Bitcoins or any kind of bonus are fake, they are completely illegal and you are not supposed to follow them, now if one follows them, then all they can do is file a complaint with your authority and Google to get them banned but bedsides than that, nothing will ever really happen, if you are scammed in Bitcoins you are scammed. So be very careful that's what I can say.
The reason why scams are so common in crypto is because people have actually made more - way more - than the scams even promise to return. See, if you bought Bitcoin back in 2009 or 2010, or even 2011 you would be ultra rich right now. Your ROI would be well in the tens of thousands of percent. With that said, when people hear about these mining scams or any Bitcoin-related scam for that matter, they think they are getting in on some great investment that is going to give them a comparable return to what many others have received from Bitcoin already. The only problem is, 99% of them are outright scams, and you are likely going to lose your money unless you are one of the first users (sitting at the top of the pyramid).