Genesis Mining is a good service, you will get 70%-100% of your investment after 2 years time. It is not a scam, but no you cannot claim for any refund, if things goes down we all lose our money.
The minimum investment anyway it's US$30 so I think you can take the risk :) If you decide to give it a go, you can use my code 'JW53Qp' to get a good discount off your orders :)