Avoid any kind of doubler. Nobody gives you money for free. Don't be silly to think you've been miraculously invited by an internet stranger to double your bucks for free and try to think logically before even contemplating giving them your money. The first thing you should have in mind is that, if someone wanted to help you out, it would make no sense for them to first ask you for your money. Either they give you money for FREE or they don't at all..
Nowadays nobody gives away free in any doubler and that if any is not legal, it's just ridiculous if they are still stuck in this doubler.
Elon Musk has been the target of many scamers and many have even been posted in this thread I think even newbies already understand how this works or not there, we see if someone is still trapped is a stupid thing that many people don't want to advise.
If you want more money you have to do a lot of work on what makes sense on your own.