optominer.com Bewertungen 

This is a scam. I personally invested a big sum of money and after a couple of weeks they changed the terms of my contract and stopped any future withdrawals, asking me to put in 4 times my original investment, which was never part of the original contract.
My funds are still locked there and I am unable to withdraw.
Opto miner and the company listed as the owner of the platform are not even FCA registered in the UK.
Don't make the same mistake as me and others who have lost their investments. Clearly, the positive reviews here are written by them. Stay away from Opto miner!

This is a scam 100%. You purchase the "contract" and after the contract fills up they automatically add a clause( that says you need to deposit 5 times the amount you originally paid for the contract otherwise they consider it a breach of contract) that you can't see when you sign up but appears after you have already have deposited your coins. They will then block you from making withdrawals or getting your principal back. Kiss your money goodbye! The other positive reviews on Trust Pilot are obviously posted by these scammers and erode the whole credibility of this platform. They don't do this with the smaller contracts, after you deposit anything above $3000 they will play the trick on you. I have screenshots of all of this including their emails and chat messages and can prove my claims.

Scam. Changed the contract AFTER I purchased and locked account when I still had 10 days left on my contract and would not let me withdraw funds
What optimizer does is let you sign up for a contract and then will change the contract to say that you have to then purchase additional contracts (5 in my case) by the time your original contract is up or you will be in breach and they can withhold withdrawals . They even withheld funding while I still had 9 days left on my original contract saying I breached it. We tested this on a separate account and the same thing happened (we have screenshots).
When you contact customer service they will gaslight you saying it’s your fault, you lied, etc
How the scam works is you start to withdraw “profits” when it’s in actually your money but then stop allowing you to withdraw unless you give them more money so they keep your funds. They asked me to put in an additional 60k in or wait 5 yrs to begin withdrawals.
I even gave them the option of just giving me 66% of my money back and they keep the rest. . Buyer beware

1000% a scam they dodge important questions say they've been around for a long time but there's no proof or backing. Buyers beware this will crash and take your money

This is a Good Platform hope this will last long Im just a Newbie Miner