if you run for referral program based pool you will face million of scam website. in this case if you upgrade plan by paying you never get paid from them. i have huge experience on this. the first things is you need follow how much they are going to return you. if your profit is too high then be sure it is scam. by the way you can join the trusted platform where you will be able to earn real btc for free.

referral program based pool.
https://altercoin.me/ref/68433